RAS via MS TermServer with Citrix Mframe

I have just installed a Chase PCI 8 port ras card in our ms terminal server running citrix metaframe. This was a FRESH server rebuild as we were having so many problems with them. Every so often the ports will stop answering incoming calls, the remote user just rings and rings and the card doesnt pick the call up until the server is rebooted then everyhtings fine for a while, any ideas!!?? ive rang chase but they said they’ve never come across anybody using Citrix with this card so cant help much!!??!?? nice answer guys.