Fatal error: Call to undefined function qtrans_useDefaultLanguage()

Hi,today i installed qtranslate and appears this on my website, now i con’t not do nothing by web, anyone knows somthing abaut how to solve it?

the error is this one:

Fatal error: Call to undefined function qtrans_useDefaultLanguage()

/wp-content/plugins/qtranslate-support-for-woocommerce/qtranslate-support-for-woocommerce.php on line 39

the php file on line 39 say:

/* Various translation filters*/
add_filter(‘the_title_attribute’, ‘qtrans_useCurrentLanguageIfNotFoundUseDefaultLanguage’, 0);
add_filter(‘woocommerce_attribute_label’, ‘qtrans_useCurrentLanguageIfNotFoundUseDefaultLanguage’, 0);
add_filter(‘woocommerce_variation_option_name’, ‘qtrans_useCurrentLanguageIfNotFoundUseDefaultLanguage’, 0);
add_filter(‘woocommerce_page_title’, ‘qtrans_useCurrentLanguageIfNotFoundUseDefaultLanguage’, 0);

thanks for any help! 🙂

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