no naxos, that's definitely wrong.
I use the Virtuemart 2.0.6 with Joomla 1.5.25.
Your problem jurxx: Can't figure it out, here it works.
Are the files and directories readable via joomla? - Do a check with the Help - "System Info" - "Directory Permissions" - are all directories Writeable?
Try to clear all the cache of the browser... and try to restart the web server...