selection buffer crash

i just implemented a selection buffer into my program im making, and for some reason, it crashes whenever i call glClear(GL_DEPTH_BUFFER_BIT); and glBegin(whatever); after i call glRenderMode(GL_SELECT);
... this prob is kickin my butt and if anyone can help... that would be excellent

ok... my friend can run the program on his computer just fine w/o crashing... so this isn't an opengl problem... its somethin else... probably a prob w/ my gfx drivers... nvidia prob messed up somewhere w/ the new ones cuz the old ones worked fine.