diff --git a/patches/november_2012/custom_field_insert_after.py b/patches/november_2012/custom_field_insert_after.py
index 403f88d..6824e7a 100644
--- a/patches/november_2012/custom_field_insert_after.py
+++ b/patches/november_2012/custom_field_insert_after.py
@@ -6,6 +6,7 @@
 	
 	for name, insert_after in webnotes.conn.sql("""select name, insert_after
 			from `tabCustom Field`"""):
-		new_insert_after = regex.sub("", insert_after)
-		webnotes.conn.set_value("Custom Field", name, "insert_after", new_insert_after)
+		if insert_after:
+			new_insert_after = regex.sub("", insert_after)
+			webnotes.conn.set_value("Custom Field", name, "insert_after", new_insert_after)
 		
\ No newline at end of file