Index: org/exolab/castor/xml/IDResolverImpl.java
===================================================================
--- org/exolab/castor/xml/IDResolverImpl.java	(Revision 6938)
+++ org/exolab/castor/xml/IDResolverImpl.java	(Arbeitskopie)
@@ -33,9 +33,13 @@
     void bind(final String id, final Object object, final boolean isValidating) 
         throws ValidationException {
         
-        if (id.equals("") || id == null) {
-            throw new ValidationException ("Invalid (empty) ID value encountered");
+        if (isValidating && id == null) {
+            throw new ValidationException ("Invalid ID value 'null' encountered");
         }
+        
+        if (isValidating && id.equals("")) {
+            throw new ValidationException ("Empty ID value encountered");
+        }
 
         if (isValidating && _idReferences.containsKey(id)) {
             if (!(id.equals("org.exolab.castor.mapping.MapItem") ||