Thanks for your answer, yes I just purchased a dedicated server it was installed and configured over the weekend, so I am sure probably has the latest PHP, SQL etc. I am running OSC 2.2 MS2. I found what the problem is quite by accident, if I put in a CVV the server hangs and will not goto confirmation screen. If I dont put in a CVV the transaction is succesful (???), I am supposed to be using CVV according to the settings in my auth.net account, so I am going to see I can do something with this new information. Also, when the checkout is successful (without CVV) it leaves the items that were purchased in users cart.
Any other comments or suggestions are greatly appreciated.