Hello,
unfortunately I ve got same problem

Engine: Joomla_1.5.9-Stable-Full_Package
Added: VirtueMart_1.1.2_eCommerce_Bundle_Joomla_1.5.9
Patch-VirtueMart-1.1.2-1.1.3
cs-CZ_joomla_lang_full.1.5.9v1
Language_Pack_for_VirtueMart_1.1.3
I changed default language for pages and for admin to czech language,but virtuemart is still in english

Anyone have solved this problem?
Every tips and advices are welcome,thank you in advance.
Best regards zmatek