crossover cable and fold@home help

I don't know if this should be here in networking or in the F@H forum so if its in the wrong place let me know and move it please.

I got my backup rig networked to my main rig through a crossover cable and i use AnalogX Proxy so i have internet on my backup rig. My backup rig can surf the web just fine loads everything like it should but i am having a intermittent problem with Fold@Home sometimes it will get wok and send info back and others it says it can't connect. sometimes it works and sometimes it don't. I got it setup to connect to the internet through port HTTP (6588) like the proxy says IE has no problem like i said and i got F@H setup the same as IE but it will not work most of the time. My backup rig is running XP Pro SP1 and my main rig is using XP Home SP2.

Oh yea sometimes it will start downloading a new core/Unit (F@H) but before it gets done it will start saying it can't connect to network or it will get done but say the core/unit is not right so it has to delete it and download another and when it tries to start downloading another it will not connect. If y'all need more info let me know and i will get it for ya