Hiya,
1st off to try is to log in to VT. Then, straight away, click the log out button. Next, go to your documents and settings folder, find the cookies folder and do a search for "volkstorque". delete anything that's found.
Now, go to
volkstorque.co.uk and log in using the login box at the top right hand side of the screen.
If all that fails make sure you're system is set to allow cookies from this site.
Cheers,
Si