Your regular expression is invalid. 'Look Ahead 'regular expression must be the last sub expression.
Үлгі өрнегі жарамсыз, 'ілеспе шарт' соңғы өрнегі болуы керек. Translators, feel free to add yourself in the text below, asking for a postcard; -), also feel free to add a section saying Translators. Kind regards, and thanks for your work - Jesper.