diff -r b3499ff87178 -r edfa63d3c26d PLCGenerator.py
--- a/PLCGenerator.py	Wed May 19 22:16:29 2010 +0200
+++ b/PLCGenerator.py	Fri May 21 13:29:01 2010 +0200
@@ -926,6 +926,8 @@
         elif type(paths) == ListType:
             vars = [self.ComputePaths(path) for path in paths]
             return JoinList([(" AND ", ())], vars)
+        elif paths is None:
+            return [("TRUE", ())]
         else:
             return eval(paths)