Index: /trunk/Mars/mbase/MParContainer.cc
===================================================================
--- /trunk/Mars/mbase/MParContainer.cc	(revision 12857)
+++ /trunk/Mars/mbase/MParContainer.cc	(revision 12858)
@@ -726,7 +726,11 @@
 void *MParContainer::DataMember(const char *member)
 {
-    const Long_t off = IsA()->GetDataMemberOffset(member);
-    if (off>0)
-        return reinterpret_cast<char*>(this)+off;
+    TDataMember *m = IsA()->GetDataMember(member);
+    if (m)
+    {
+        const Long_t off = m->GetOffset();
+        if (off>0)
+            return reinterpret_cast<char*>(this)+off;
+    }
 
     *fLog << err << "Data member '" << member << "' not found in " << GetDescriptor() << endl;