diff --git a/C/cdmgr.c b/C/cdmgr.c
index de4cd2797..8bf8d6ac0 100644
--- a/C/cdmgr.c
+++ b/C/cdmgr.c
@@ -11,8 +11,11 @@
 * File:		cdmgr.c							 *
 * comments:	Code manager						 *
 *									 *
-* Last rev:     $Date: 2008-03-22 23:35:00 $,$Author: vsc $						 *
+* Last rev:     $Date: 2008-03-24 23:48:47 $,$Author: vsc $						 *
 * $Log: not supported by cvs2svn $
+* Revision 1.221  2008/03/22 23:35:00  vsc
+* fix bug in all_calls
+*
 * Revision 1.220  2008/03/17 18:31:16  vsc
 * fix breakage in module system
 * disable stack writing in error for now
@@ -3354,7 +3357,7 @@ all_calls(void)
   } else {
     ts[2] = ts[3] = TermNil;
   }
-  return(Yap_MkApplTerm(f,4,ts));
+  return Yap_MkApplTerm(f,4,ts);
 }
 
 Term
diff --git a/C/errors.c b/C/errors.c
index d663efa6c..080944a0e 100644
--- a/C/errors.c
+++ b/C/errors.c
@@ -1328,6 +1328,20 @@ Yap_Error(yap_error_number type, Term where, char *format,...)
       serious = TRUE;
     }
     break;
+  case RESOURCE_ERROR_MAX_THREADS:
+    {
+      int i;
+      Term ti[1];
+
+      i = strlen(tmpbuf);
+      ti[0] = MkAtomTerm(Yap_LookupAtom("max_threads"));
+      nt[0] = Yap_MkApplTerm(Yap_MkFunctor(Yap_LookupAtom("resource_error"),1), 1, ti);
+      tp = tmpbuf+i;
+      psize -= i;
+      fun = Yap_MkFunctor(Yap_LookupAtom("error"),2);
+      serious = TRUE;
+    }
+    break;
   case SYNTAX_ERROR:
     {
       int i;
diff --git a/C/threads.c b/C/threads.c
index c4785d78b..a995c5206 100644
--- a/C/threads.c
+++ b/C/threads.c
@@ -47,11 +47,13 @@ allocate_new_tid(void)
 	(ThreadHandle[new_worker_id].in_use == TRUE ||
 	 ThreadHandle[new_worker_id].zombie == TRUE) )
     new_worker_id++;
-  pthread_mutex_lock(&(ThreadHandle[new_worker_id].tlock));
-  ThreadHandle[new_worker_id].in_use = TRUE;
+  if (new_worker_id < MAX_WORKERS) {
+    pthread_mutex_lock(&(ThreadHandle[new_worker_id].tlock));
+    ThreadHandle[new_worker_id].in_use = TRUE;
+  } else {
+    new_worker_id = -1;
+  }
   UNLOCK(ThreadHandlesLock);
-  if (new_worker_id == MAX_WORKERS) 
-    return -1;
   return new_worker_id;  
 }
 
@@ -180,7 +182,12 @@ thread_run(void *widp)
 static Int
 p_thread_new_tid(void)
 {
-  return Yap_unify(MkIntegerTerm(allocate_new_tid()), ARG1);
+  int new_worker = allocate_new_tid();
+  if (new_worker == -1) {
+    Yap_Error(RESOURCE_ERROR_MAX_THREADS, MkIntegerTerm(MAX_WORKERS), "");
+    return FALSE;
+  }
+  return Yap_unify(MkIntegerTerm(new_worker), ARG1);
 }
 
 static void
diff --git a/H/Yap.h b/H/Yap.h
index 8fb19e8c9..ca2bba203 100644
--- a/H/Yap.h
+++ b/H/Yap.h
@@ -10,7 +10,7 @@
 * File:		Yap.h.m4						 *
 * mods:									 *
 * comments:	main header file for YAP				 *
-* version:      $Id: Yap.h,v 1.28 2008-03-13 18:41:50 vsc Exp $	 *
+* version:      $Id: Yap.h,v 1.29 2008-03-24 23:48:47 vsc Exp $	 *
 *************************************************************************/
 
 #include "config.h"
@@ -471,6 +471,7 @@ typedef enum
   REPRESENTATION_ERROR_CHARACTER,
   REPRESENTATION_ERROR_CHARACTER_CODE,
   REPRESENTATION_ERROR_MAX_ARITY,
+  RESOURCE_ERROR_MAX_THREADS,
   RETRY_COUNTER_UNDERFLOW,
   SYNTAX_ERROR,
   SYSTEM_ERROR,
diff --git a/pl/hacks.yap b/pl/hacks.yap
index a7a4940ef..461aeb9f6 100644
--- a/pl/hacks.yap
+++ b/pl/hacks.yap
@@ -11,7 +11,7 @@
 * File:		utilities for messing around in YAP internals.		 *
 * comments:	error messages for YAP					 *
 *									 *
-* Last rev:     $Date: 2008-03-17 18:31:16 $,$Author: vsc $						 *
+* Last rev:     $Date: 2008-03-24 23:48:47 $,$Author: vsc $						 *
 *									 *
 *									 *
 *************************************************************************/
@@ -74,7 +74,10 @@ display_stack_info([],[Env|Envs],I,Cont) -->
 	{ I1 is I-1 },
 	display_stack_info([], Envs, I1, NCont).
 display_stack_info([CP|LCPs],[Env|LEnvs],I,Cont) -->
-	{ yap_hacks:continuation(Env, _, NCont, CB), I1 is I-1 },
+	{
+	 yap_hacks:continuation(Env, _, NCont, CB),
+	 I1 is I-1
+	},
 	( { CP == Env, CB < CP } ->
 	    % if we follow choice-point and we cut to before choice-point
 	    % we are the same goal
diff --git a/pl/messages.yap b/pl/messages.yap
index 762b6f542..d3332d26d 100644
--- a/pl/messages.yap
+++ b/pl/messages.yap
@@ -11,7 +11,7 @@
 * File:		utilities for displaying messages in YAP.		 *
 * comments:	error messages for YAP					 *
 *									 *
-* Last rev:     $Date: 2008-03-17 18:31:16 $,$Author: vsc $						 *
+* Last rev:     $Date: 2008-03-24 23:48:47 $,$Author: vsc $						 *
 *									 *
 *									 *
 *************************************************************************/
@@ -190,7 +190,7 @@ system_message(error(permission_error(access,static_procedure,P), Where)) -->
 	[ 'PERMISSION ERROR- ~w: cannot access static procedure ~w' - [Where,P] ].
 system_message(error(permission_error(alias,new,P), Where)) -->
 	[ 'PERMISSION ERROR- ~w: cannot create alias ~w' - [Where,P] ].
-system_message(error(permission_error(create,array,P), Where)) -->
+system_message(error(permission_error(create,Name,P), Where)) -->
 	{ object_name(Name, ObjName) },
 	[ 'PERMISSION ERROR- ~w: cannot create ~a ~w' - [Where,ObjName,P] ].
 system_message(error(permission_error(input,binary_stream,Stream), Where)) -->
@@ -237,6 +237,8 @@ system_message(error(representation_error(character_code), Where)) -->
 	[ 'REPRESENTATION ERROR- ~w: expected character code' - [Where] ].
 system_message(error(representation_error(max_arity), Where)) -->
 	[ 'REPRESENTATION ERROR- ~w: number too big' - [Where] ].
+system_message(error(resource_error(max_threads), Where)) -->
+	[ 'RESOURCE ERROR- too many open threads' - [Where] ].
 system_message(error(syntax_error(G,0,Msg,[],0,0), _)) -->
 	[ 'SYNTAX ERROR: ~a' - [G,Msg] ].
 system_message(error(syntax_error(_,_,_,Term,Pos,Start), Where)) -->