--- a/runtime/PLCObject.py	Fri Apr 10 07:53:42 2009 +0200
+++ b/runtime/PLCObject.py	Fri Apr 10 07:55:55 2009 +0200
@@ -226,7 +226,9 @@
             runtime_begin()
 
     def FinishRuntimePy(self):
-        runtime_cleanup = self.python_threads_vars.get("_runtime_cleanup",None)
+        runtime_cleanup = None
+        if self.python_threads_vars is not None:
+            runtime_cleanup = self.python_threads_vars.get("_runtime_cleanup",None)
         if runtime_cleanup is not None:
             runtime_cleanup()
         if self.hmi_frame is not None: