Hi guys,
Stéphane from Faboba made a fix for Falang version 3.4.3 to make it work properly with VirtueMart (he said he would include it in a better way in next release of FaLang but for now you need to):
1. replace this file by the attached falangdriver.php (unzip the archive):
plugins/system/falangdriver/falangdriver.php
2. edit this file modules/mod_virtuemart_category/mod_virtuemart_category.php
on line 30 you need to add:
var_dump(JFactory::getLanguage()->getTag());
var_dump(VmLanguage::$currLangTag);