diff --git a/scheme/httpd/surflets/packages.scm b/scheme/httpd/surflets/packages.scm
index 53e8686..1b87d95 100644
--- a/scheme/httpd/surflets/packages.scm
+++ b/scheme/httpd/surflets/packages.scm
@@ -166,8 +166,8 @@
 	  make-submit-button
 	  make-reset-button
 	  make-image-button
-	  try-input-field-value
 	  input-field-value
+	  raw-input-field-value
 	  input-field-binding
 
 	  make-address
diff --git a/scheme/httpd/surflets/surflets.scm b/scheme/httpd/surflets/surflets.scm
index 6853776..2887fed 100644
--- a/scheme/httpd/surflets/surflets.scm
+++ b/scheme/httpd/surflets/surflets.scm
@@ -575,7 +575,7 @@
 
 ;; <input-field>: '(input-field . <real-input-field>)
 ;; <real-input-field>: #{Input-field "name"}
-(define (input-field-value input-field bindings)
+(define (raw-input-field-value input-field bindings)
   (let ((input-field (cadr input-field)))
     (cond
      ((input-field-get-bindings? input-field)
@@ -587,18 +587,20 @@
       (error "no such input-field" input-field bindings)))))
 
 ;; Trys to get a value for INPUT-FIELD in BINDINGS. If this fails
-;; (i.e. INPUT-FIELD-VALUE returns an error), the default-value is
+;; (i.e. RAW-INPUT-FIELD-VALUE returns an error), the default-value is
 ;; returned. The default-value defaults to #f. NOTE: If you do this
 ;; with input-fields whose valid values may be the same as the default
 ;; value, you cannot determine by the result if there was such a value
-;; or not. Keep in mind, that INPUT-FIELD-VALUE returns also an error,
-;; if there was not such an input field.
-(define (try-input-field-value input-field bindings . maybe-default)
+;; or not. Keep in mind, that RAW-INPUT-FIELD-VALUE returns also an
+;; error, if there was not such an input field. This makes
+;; INPUT-FIELD-VALUE working with checkbox input fields because they
+;; miss if they are not checked.
+(define (input-field-value input-field bindings . maybe-default)
   (let ((default (:optional maybe-default #f)))
     (with-fatal-error-handler
      (lambda (condition more)
        default)
-     (input-field-value input-field bindings))))
+     (raw-input-field-value input-field bindings))))
 
 (define (real-input-field-binding input-field bindings)
   (assoc (input-field-name input-field) bindings))
diff --git a/scheme/httpd/surflets/web-server/root/htdocs/index.html b/scheme/httpd/surflets/web-server/root/htdocs/index.html
index ef187fc..ad68e63 100644
--- a/scheme/httpd/surflets/web-server/root/htdocs/index.html
+++ b/scheme/httpd/surflets/web-server/root/htdocs/index.html
@@ -13,6 +13,7 @@
       <li><a href="servlet/calculate.scm">Simple Calculator</a></li>
       <li><a href="servlet/byte-input.scm">Byte Input Widget</a></li>
       <li><a href="servlet/simple-servlet.scm">Simple Servlet</a></li>
+      <li><a href="servlet/spaceship.scm">Spaceship builder</a></li>
 <!--       <li><a href=/servlet/test.scm>A test servlet</a></li> -->
       <li><a href="servlet/admin.scm">Servlet Administration</a></li>
       <li><a href=index.html>This file</a></li>
@@ -23,7 +24,7 @@
     <hr>
     <!-- Created: Thu Aug 22 16:44:16 CEST 2002 -->
     <!-- hhmts start -->
-Last modified: Sun Nov  3 15:24:22 CET 2002
+Last modified: Tue Nov  5 10:39:46 CET 2002
 <!-- hhmts end -->
   </body>
 </html>
diff --git a/scheme/httpd/surflets/web-server/root/surflets/add2.scm b/scheme/httpd/surflets/web-server/root/surflets/add2.scm
index 61186d9..e68c84d 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/add2.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/add2.scm
@@ -27,11 +27,9 @@
 			 (p (URL "/" "Return to main menu.") (br)
 			    (URL "add2.scm" "Start new calculation."))))))))
 	(if result
-	    (with-fatal-error-handler
-	     (lambda (condition more)
-	       (get-number input-text "Please enter a valid number."))
-	     (input-field-value number-input-field 
-				(form-query (http-url:search (request:url result)))))
+	    (or (input-field-value number-input-field 
+				   (form-query (http-url:search (request:url result))))
+		(get-number input-text "Please enter a valid number."))
 	    (get-number input-text "Please enter a number."))))
 
     (define (get-number1)
diff --git a/scheme/httpd/surflets/web-server/root/surflets/admin-handler.scm b/scheme/httpd/surflets/web-server/root/surflets/admin-handler.scm
index 997d814..ccd86b5 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/admin-handler.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/admin-handler.scm
@@ -55,18 +55,17 @@
 	 ((returned-via? return-address bindings)
 	  (return-to-main-page req))
 	 ((input-field-binding submit-timeout bindings)
-	  (with-fatal-error-handler
-	   (lambda (condition more)
-	     (handler-options req "Please enter a valid, positive integer number"))
 	   (let ((result (input-field-value number-field bindings)))
-	     (if (and (integer? result)
-		      (> result 0))
-		 (begin
-		   (set-options-instance-lifetime result)
-		   (handler-options req 
-				    (format #f "Instance lifetime changed to ~a." 
-					    (options-instance-lifetime))))
-		  (error "not a positive integer")))))
+	     (if result
+		 (if (and (integer? result)
+			  (> result 0))
+		     (begin
+		       (set-options-instance-lifetime result)
+		       (handler-options req 
+					(format #f "Instance lifetime changed to ~a." 
+						(options-instance-lifetime))))
+		     (error "not a positive integer"))
+		 (handler-options req "Please enter a valid, positive integer number"))))
 	 ((input-field-binding submit-cache bindings)
 	  (let ((cache-plugins? (if (input-field-binding cache-checkbox bindings)
 				    #t 
diff --git a/scheme/httpd/surflets/web-server/root/surflets/admin-profiling.scm b/scheme/httpd/surflets/web-server/root/surflets/admin-profiling.scm
index 7738c84..671ca9e 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/admin-profiling.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/admin-profiling.scm
@@ -89,10 +89,7 @@
 	 ((returned-via? reset-return-address bindings)
 	  (reset-and-return-to-main-page req))
 	 (else
-	  (let ((new-gnuplot-location (with-fatal-error-handler
-				       (lambda (condition more)
-					 #f)
-				       (input-field-value input-field bindings))))
+	  (let ((new-gnuplot-location (input-field-value input-field bindings)))
 	    (if (and new-gnuplot-location
 		     (file-executable? new-gnuplot-location))
 		(begin
diff --git a/scheme/httpd/surflets/web-server/root/surflets/admin-servlets-cb.scm b/scheme/httpd/surflets/web-server/root/surflets/admin-servlets-cb.scm
index 3c76b56..485a303 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/admin-servlets-cb.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/admin-servlets-cb.scm
@@ -58,12 +58,9 @@
 	    (values
 	     action
 	     (filter-map (lambda (checkbox table-element)
-			   (if(with-fatal-error-handler
-			       (lambda (condition more)
-				 #f)
-			       (input-field-value checkbox bindings))
-			      table-element
-			      #f))
+			   (if (input-field-value checkbox bindings)
+			       table-element
+			       #f))
 			 checkboxes
 			 table-elements)))))
 
diff --git a/scheme/httpd/surflets/web-server/root/surflets/admin-servlets.scm b/scheme/httpd/surflets/web-server/root/surflets/admin-servlets.scm
index f94c4f4..94aa3bc 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/admin-servlets.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/admin-servlets.scm
@@ -58,9 +58,7 @@
 	    (values #f #f)
 	    (values action
 		    (filter-map (lambda (checkbox table-element)
-				  (if (with-fatal-error-handler
-				       (lambda (c m) #f)
-				       (input-field-value checkbox bindings))
+				  (if (input-field-value checkbox bindings)
 				      table-element
 				      #f))
 				checkboxes
diff --git a/scheme/httpd/surflets/web-server/root/surflets/byte-input.scm b/scheme/httpd/surflets/web-server/root/surflets/byte-input.scm
index a4fd330..64ca11e 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/byte-input.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/byte-input.scm
@@ -27,9 +27,8 @@
 	     (if (null? checkboxes)
 		 sum
 		 (loop (+ sum (string->number
-			       (with-fatal-error-handler
-				(lambda (condition decline) "0")
-				(input-field-value (car checkboxes) bindings))))
+			       (or (input-field-value (car checkboxes) bindings)
+				   "0")))
 		       (cdr checkboxes)))))
 	 checkboxes)))
 
diff --git a/scheme/httpd/surflets/web-server/root/surflets/calculate-cb.scm b/scheme/httpd/surflets/web-server/root/surflets/calculate-cb.scm
index e8a9dfd..be992f2 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/calculate-cb.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/calculate-cb.scm
@@ -37,7 +37,7 @@
       (make-callback 
        (lambda (req)
 	 (change-operator
-	  ;; This yields an error only when the browser doing wrong.
+	  ;; This yields an error only when the browser is doing wrong.
 	  (input-field-value operator-input-field
 			     (get-bindings req))))
        ))
@@ -78,14 +78,8 @@
 			       (td ,(make-submit-button 
 				     '(@ (value "change operator"))))))))))))
 	     (bindings (get-bindings req)))
-	(let ((number1 
-	       (with-fatal-error-handler 
-		(lambda (c d) #f)
-		(input-field-value number-field1 bindings)))
-	      (number2 
-	       (with-fatal-error-handler 
-		(lambda (c d) #f)
-		(input-field-value number-field2 bindings))))
+	(let ((number1 (input-field-value number-field1 bindings))
+	      (number2 (input-field-value number-field2 bindings)))
 	  (if number1
 	      (if number2
 		  (calculate operator-pair number1 number2)
diff --git a/scheme/httpd/surflets/web-server/root/surflets/calculate.scm b/scheme/httpd/surflets/web-server/root/surflets/calculate.scm
index 5ef7b44..7fdc159 100644
--- a/scheme/httpd/surflets/web-server/root/surflets/calculate.scm
+++ b/scheme/httpd/surflets/web-server/root/surflets/calculate.scm
@@ -69,12 +69,8 @@
 			  (hr)
 			  (p (URL "/" "Return to main menu."))))))))
 	     (bindings (get-bindings req)))
-	(let ((number1 (with-fatal-error-handler 
-			(lambda (c d) #f)
-			(input-field-value number-field1 bindings)))
-	      (number2 (with-fatal-error-handler 
-			(lambda (c d) #f)
-			(input-field-value number-field2 bindings))))
+	(let ((number1 (input-field-value number-field1 bindings))
+	      (number2 (input-field-value number-field2 bindings)))
 	  (cond
 	   ((input-field-binding calculate-button bindings)
 	    (if number1