better error reporting

Source/cmLoadCommandCommand.cxx

@@ -206,6 +206,11 @@ bool cmLoadCommandCommand::InitialPass(std::vector<std::string> const& argsIn)
       // create a function blocker and set it up
       cmLoadedCommand *f = new cmLoadedCommand();
       f->m_commandName = (*nameFunction)();
+      if (!initFunction)
+        {
+        this->SetError("Attempt to load command failed. No init function found.");
+        return false;
+        }
       (*initFunction)(&f->info);
       m_Makefile->AddCommand(f);
       }