Index: geant4_vmc/source/run/src/TGeant4.cxx
===================================================================
--- geant4_vmc/source/run/src/TGeant4.cxx	(revision 398)
+++ geant4_vmc/source/run/src/TGeant4.cxx	(working copy)
@@ -1004,7 +1004,7 @@
 /// Return name of G4 particle specified by pdg.
 
   if ( ! CheckG4ApplicationState("ParticleName", G4State_Idle, true ) ) 
-    return 0;
+    return "";
 
   return fPhysicsManager->ParticleName(pdg);
 }