We are having some issues after updating to Virtuemart 2.6. Add to cart and other dynamic functions like product options with price recalcuation don't work anymore. One thing I noticed is that in the Virtuemart 2.6 config there is no VmSiteURL anymore. This I had to change in previous versions to make this work with Gtranslate.
How to make this work????
Or, do you guys cache a version of the site on your server? In this case that might be the problem.