diff --git a/src/ikarus.boot b/src/ikarus.boot
index b237d1b..06bf600 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.library-manager.ss b/src/ikarus.library-manager.ss
index aeb9c70..487beaa 100644
--- a/src/ikarus.library-manager.ss
+++ b/src/ikarus.library-manager.ss
@@ -45,10 +45,6 @@
     (find-library-by
       (lambda (x) (equal? (library-name x) name))))
 
-  (define (find-library-by-name/die name)
-    (or (find-library-by-name name)
-        (error #f "cannot find library ~s" name)))
-
   (define (find-library-by-spec/die spec)
     (let ([id (car spec)])
       (or (find-library-by
diff --git a/src/ikarus.syntax.ss b/src/ikarus.syntax.ss
index 0902c9f..9bd3c76 100644
--- a/src/ikarus.syntax.ss
+++ b/src/ikarus.syntax.ss
@@ -117,6 +117,7 @@
             (make-vector (vector-length sym*) 0))))))
   (define (unseal-rib! rib)
     (when (rib-sealed/freq rib)
+      ;(printf "[ribsize ~s]\n" (vector-length (rib-sealed/freq rib)))
       (set-rib-sealed/freq! rib #f)
       (set-rib-sym*! rib (vector->list (rib-sym* rib)))
       (set-rib-mark**! rib (vector->list (rib-mark** rib)))
@@ -2093,6 +2094,8 @@
         [(prefix) (error #f "prefix found")]
         [else 
          (let ([lib (find-library-by-name spec)])
+           (unless lib
+             (error 'import "cannot find library satisfying ~s" spec))
            (let-values ([(s _r) (library-subst/env lib)])
               (values s lib)))]))
     (cond