I bet you were running "other" proxies before Nproxy that used Java i made a thread about this some time ago that the new java update causes co to crash due to congestion errors so if ya have newest java runtimes installed and try loading something that uses that java I.E. Internet explorer,limewire or Lakes Qoproxy or anything else that makes the java runtimes load while co is running your co clients will lag out and crash.
This is why i told people not to compile there proxys in the new java but they didn't listen.I am willing to bet this is your issue because if you used Nproxy i'm sure as heck ya used all the others too and all the Qoproxies posted here are compiled to run on the new buggy java runtimes.
So ya have a few choices have your co's crash so u can aimbot or speedhack or whatever it is ya use proxy for or NOT run proxy or get the source yourself and fix it and recompile it in version 5 or below java..
Or last but not least you can uninstall the newest java update from add/remove in control panel which is currently SE runtime environment 6 and your co will run perfectly.
SE v 1.4.2 SDK with version 5 runtimes <<--- is most stable release of java that proxy SHOULD be compiled to run on without effecting anything else.
Hope this helps you