Problem choosing payment method at checkout

[rocarly25]

Hi! I have a problem choosing a payment method and one Page checkout plugin. I have 2 payments method set in my store, Authorized.net(for credit cards) and Cash (standard). If I choose Cash and click Next for next step then a validation error appear in the Credit Card Number field and I'm not able to go. It's a Virtuemart issue? Authorize.net paymenth method? One checkout page? I can't find anything online.

I'm using Virtuemart 2.6.10
Joomla 2.5.24
gk_storebox
Rupostel One Page Checkout 2.0.

Thanks in advance

[GJC Web Design]

It is a problem for either Rupostal or Gavik  - they are who you ask....