diff --git a/C/cdmgr.c b/C/cdmgr.c
index c3b1baf59..715406717 100644
--- a/C/cdmgr.c
+++ b/C/cdmgr.c
@@ -866,7 +866,8 @@ addclause(Term t, CODEADDR cp, int mode, int mod)
     spy_flag = TRUE;
   if (mode == consult)
     not_was_reconsulted(p, t, TRUE);
-  if (Error_TYPE == PERMISSION_ERROR_MODIFY_STATIC_PROCEDURE)
+  /* always check if we have a valid error first */
+  if (ErrorMessage && Error_TYPE == PERMISSION_ERROR_MODIFY_STATIC_PROCEDURE)
     return;
   if (!is_dynamic(p)) {
     Clause     *clp = ClauseCodeToClause(cp);
diff --git a/C/compiler.c b/C/compiler.c
index 68883143a..33de2c5f7 100644
--- a/C/compiler.c
+++ b/C/compiler.c
@@ -2718,7 +2718,7 @@ cclause(Term inp_clause, int NOfArgs, int mod)
   /* may botch while doing a different module */
 
   /* first, initialise CompilerBotch to handle all cases of interruptions */
-  ErrorMessage = NIL;
+  ErrorMessage = NULL;
   if ((botch_why = setjmp(CompilerBotch)) == 3) {
     /* out of local stack, just duplicate the stack */
     restore_machine_regs();
@@ -2759,7 +2759,7 @@ cclause(Term inp_clause, int NOfArgs, int mod)
     return(0);
   }
  restart_compilation:
-  if (ErrorMessage != NIL) {
+  if (ErrorMessage != NULL) {
     reset_vars();
     return (0);
   }
diff --git a/C/sysbits.c b/C/sysbits.c
index 063d1a4a7..764779c98 100644
--- a/C/sysbits.c
+++ b/C/sysbits.c
@@ -1111,9 +1111,10 @@ InteractSIGINT(int ch) {
       unsigned long int heap_space_taken = 
 	(unsigned long int)(Unsigned(HeapTop)-Unsigned(HeapBase));
       double frag = (100.0*(heap_space_taken-HeapUsed))/heap_space_taken;
-      YP_fprintf(YP_stderr, "Code Space:  %ld (%ld bytes used, fragmentation %.3f%%).\n", 
-		 (unsigned long int)(Unsigned (AuxTop) - Unsigned (HeapBase)),
-		 (unsigned long int)(Unsigned(HeapTop)-Unsigned(HeapBase)),
+      YP_fprintf(YP_stderr, "Code Space:  %ld (%ld bytes needed, %ld bytes used, fragmentation %.3f%%).\n", 
+		 (unsigned long int)(Unsigned (H0) - Unsigned (HeapBase)),
+                 (unsigned long int)(Unsigned(HeapTop)-Unsigned(HeapBase)),
+		 (unsigned long int)(HeapUsed),
 		 frag);
       YP_fprintf(YP_stderr, "Stack Space: %ld (%ld for Global, %ld for local).\n", 
 		 (unsigned long int)(sizeof(CELL)*(LCL0-H0)),