Stuck on Confirm, No PayPal page

[otomikmedia]

Running Joomla 1.5.20 and VM 1.1.5.
VM used to process orders, send confirmations, then redirect to PayPal. Now it doesn't and all it does is issue a 404 page (http://www.devenenterprise.com/virtuemart).
Most postings here don't seem to address this issue.
My URL is devenenterprise.com
Can someone suggest a solution?
thanks.

[otomikmedia]

Sorry, but I got it fixed. I found from another post that the search engine friendly button must be deactivated.