[Plugin: qTranslate] php fatal error

Catchable fatal error: Object of class __PHP_Incomplete_Class could not be converted to string in /home/usr/test/wp-content/plugins/qtranslate/qtranslate_services.php

running on a test environment (i can’t provide a link) with a fresh WP install and default theme

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