diff --git a/src/codegen.c b/src/codegen.c
index 808b66e7..c0142599 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -441,10 +441,11 @@ pic_codegen(pic_state *pic, pic_value obj, struct pic_env *env)
   if (! pic->jmp) {
     jmp_buf jmp;
 
-    pic->jmp = &jmp;
-    if (setjmp(*pic->jmp) != 0) {
+    if (setjmp(jmp) == 0) {
+      pic->jmp = &jmp;
+    }
+    else {
       /* error occured */
-
       pic->jmp = NULL;
       return NULL;
     }
diff --git a/src/pair.c b/src/pair.c
index 1a60e184..bbd17e5f 100644
--- a/src/pair.c
+++ b/src/pair.c
@@ -18,6 +18,9 @@ pic_car(pic_state *pic, pic_value obj)
 {
   struct pic_pair *pair;
 
+  if (! pic_pair_p(obj)) {
+    pic_error(pic, "pair required");
+  }
   pair = (struct pic_pair *)obj.u.data;
 
   return pair->car;
@@ -28,6 +31,9 @@ pic_cdr(pic_state *pic, pic_value obj)
 {
   struct pic_pair *pair;
 
+  if (! pic_pair_p(obj)) {
+    pic_error(pic, "pair required");
+  }
   pair = (struct pic_pair *)obj.u.data;
 
   return pair->cdr;
diff --git a/src/vm.c b/src/vm.c
index bbe0c4ea..8b2c68e9 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -64,6 +64,7 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
 {
   struct pic_code *pc;
   int ai = pic_gc_arena_preserve(pic);
+  jmp_buf jmp;
 
 #if PIC_DIRECT_THREADED_VM
   static void *oplabels[] = {
@@ -76,6 +77,13 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
 
   pc = proc->u.irep->code;
 
+  if (setjmp(jmp) == 0) {
+    pic->jmp = &jmp;
+  }
+  else {
+    goto L_RAISE;
+  }
+
   /* adjust call frame */
   pic->sp[0] = pic_obj_value(proc);
   pic->ci->argc = 1;
@@ -158,11 +166,17 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
       pic_value v;
       pic_callinfo *ci;
 
-      v = POP();
-      ci = POPCI();
-      pc = ci->pc;
-      pic->sp -= ci->argc;
-      PUSH(v);
+    L_RAISE:
+      if (pic->errmsg) {
+	goto L_STOP;
+      }
+      else {
+	v = POP();
+	ci = POPCI();
+	pc = ci->pc;
+	pic->sp -= ci->argc;
+	PUSH(v);
+      }
       NEXT;
     }
     CASE(OP_LAMBDA) {
@@ -232,8 +246,14 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
     CASE(OP_STOP) {
       pic_value val;
 
+    L_STOP:
       val = POP();
 
+      pic->jmp = NULL;
+      if (pic->errmsg) {
+	return pic_undef_value();
+      }
+
 #if VM_DEBUG
       puts("**VM END STATE**");
       printf("stbase = %p\nsp = %p\n", pic->stbase, pic->sp);
diff --git a/tools/main.c b/tools/main.c
index d6011621..a8f752cc 100644
--- a/tools/main.c
+++ b/tools/main.c
@@ -87,6 +87,11 @@ main()
       goto next;
     }
     v = pic_run(pic, proc, pic_nil_value());
+    if (pic_undef_p(v)) {
+      printf("runtime error: %s\n", pic->errmsg);
+      pic->errmsg = NULL;
+      goto next;
+    }
 
     /* print */
     printf("=> ");