Okay, that's what I thought. A recent build (recent in terms of build number, not date... lol) of paintball2 made use of some SSE-required code that increased the accuracy of predictions made on the client and server. P/PPro processors don't have SSE capabilities, and that's why you're being thrown the 'Illegal Instruction' error.
jitspoe can build you a B19 Non-SSE binary that will run on this server, but players on the server may run into prediction problems or 'misses'. That basically means that movement may not be as fluid since these calculations are being made without SSE on the server, and with SSE on the client. I didn't test it too much so I can't really say how bad the prediction misses really are.
I suppose you could also download the source and compile it yourself, if you can find somewhere in the makefile to disable SSE. If you're running into problems with it, I can help out. Forum PMs seem to be the best way to get ahold of me these days, unless your name is Apocalypse.
