are you trying to use bsp col and standard col on the same object? This definitely won't work. Form my experience if you use a dummy obj for bsp col, bsp col on the camera, and a second dummy obj for auto standard col, everything should work except automatic col wont backtrack, but you can still register the collisions correctly. this is a Confirmed bug, but you still shouldn't fall thru -AS FAR AS HL BSPs are concerned. Mayber further problems exist with Quake bsps
I did experience falling thru when messing with two collision types on One objects - they would sort of cancel eachother, or better, flip flop between which col type had priority...
hopefully this will all be sorted out in the next few patches
-RUST-