Feel free to move this post to wherever it belongs. I am runnning firefox on Ubuntu Linux.
If I attempt to log using the Login form at the top of the www.virtuemart.com page I get "invalid token" and a blank page after entering my password and submitting.
Never tried logging in there. What were you trying to do?
go to Components > Virtuemart > Admin > Configuration > Security
On the Site URL and SECUREURL put your store address with "www".
example:
WRONG:
http://yoursite.com
GOOD:
http://www.yoursite.com
I had the same problem and this fixed it.