--- /usr/lib/pymodules/python2.6/univention/admin/mapping.py.orig	2013-08-07 07:05:18.356001523 -0400
+++ /usr/lib/pymodules/python2.6/univention/admin/mapping.py	2013-08-07 06:31:04.192001491 -0400
@@ -92,6 +92,8 @@
 
 def mapUNIX_TimeInterval( value ):
 	unit = 'seconds'
+	if not value:
+		value = 0
 	if isinstance( value, ( tuple, list ) ):
 		if len( value ) > 1:
 			unit = value[ 1 ]