Hi!
I have a demo site with one new fresh install of J2.5 and VM2.0.10
I installed a swedish language pack and set the language to swedish on the site.
After that, the products are gone frontend? Why?
Most likely because you started to enter swedish language product descriptions into english language database tables.
See here: http://forum.virtuemart.net/index.php?topic=104901.msg349135#msg349135 (http://forum.virtuemart.net/index.php?topic=104901.msg349135#msg349135)
and here: http://forum.virtuemart.net/index.php?topic=95970.msg325592#msg325592 (http://forum.virtuemart.net/index.php?topic=95970.msg325592#msg325592)