Work around issue 131 by checking for empty handles

src/top.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 788 matching lines @@
         reinterpret_cast<void*>(*message_obj);
     }
   }
 
   // Notify debugger of exception.
   Debugger::OnException(exception_handle, report_exception);
 
   if (report_exception) {
     if (message != NULL) {
       MessageHandler::ReportMessage(message);
-    } else {
+    } else if (!message_obj.is_null()) {
       MessageHandler::ReportMessage(location, message_obj);
     }
   }
 
   // NOTE: Notifying the debugger or reporting the exception may have caused
   // new exceptions. For now, we just ignore that and set the pending exception
   // to the original one.
   set_pending_exception(*exception_handle);
 }
 
@@ skipping 73 matching lines @@
   Top::break_access_->Lock();
 }
 
 
 ExecutionAccess::~ExecutionAccess() {
   Top::break_access_->Unlock();
 }
 
 
 } }  // namespace v8::internal