404 errors with permalinks

my default web site is english..recently i installed qtranslate plugin for to use as turkish as well..

in my english web site everything working fine:
http://gimmickgifts.com/product-category/ballons/

when i try to translate to turkish and when i click same link it gives me error:
http://gimmickgifts.com/urun-kategori/balonlar/?lang=TR
404, That page doesn’t exist..

can you please help ?
thanks

http://ww.wp.xz.cn/plugins/qtranslate/