[psychonic]

Something is still wrong with your steamclient binary regardless if you're getting those errors. It's actually possible that L4D1 just ships with a very, very old one, maybe from before that interface existed.

You can try replacing steamclient.so, libtier0_s.so, and libvstdlib_s.so with ones from a newer game. (Don't replace libsteam_api.so)

#3 wasn't out of hate, just stereotyping.