Index: modules/univention/admin/mapping.py
===================================================================
--- modules/univention/admin/mapping.py	(Revision 57356)
+++ modules/univention/admin/mapping.py	(Arbeitskopie)
@@ -73,11 +82,18 @@
 	if list != 'None':
 		return list
 
+def StringToInt(value):
+	try:
+		result = int(value)
+	except ValueError:
+		return 0
+	return result
+
 def unmapUNIX_TimeInterval( value ):
 	if type(value) == types.ListType:
-		value = int(value[0])
+		value = StringToInt(value[0])
 	else:
-		value = int(value)
+		value = StringToInt(value)
 	unit = 'seconds'
 	if value % 60 == 0:
 		value /= 60
@@ -95,9 +111,9 @@
 	if isinstance( value, ( tuple, list ) ):
 		if len( value ) > 1:
 			unit = value[ 1 ]
-		value = int( value[ 0 ] )
+		value = StringtoInt( value[ 0 ] )
 	else:
-		value = int( value )
+		value = StringToInt( value )
 	if unit == 'days':
 		value *= 24 * 60 * 60
 	elif unit == 'hours':