diff -r 75d242975792 -r 1158231e7360 common/mixins.py
--- a/common/mixins.py	Fri Jan 23 19:18:28 2009 +0100
+++ b/common/mixins.py	Fri Jan 23 19:21:29 2009 +0100
@@ -165,7 +165,11 @@
     
     @property
     def state(self):
-        return self.in_state[0].name
+        try:
+            return self.in_state[0].name
+        except IndexError:
+            self.warning('entity %s has no state', self)
+            return None
     
     @property
     def displayable_state(self):