probelm

Everytime I join a game an error appears that says Can not load libary and gives this location C:\SIERRA\CounterStrike\ESF\cl_dlls\client.dll anybody know how to fix this?

i downloaded 1.1 alright and it works and what not but then i tryed to connect to a server and right before i'm about ot get in it says my client.dll is different from the serevrs client dll and i was so i dunno i thought maybe that i went into a server that was running 1.0 but then i tryed an...