Gmod server error

[mhorn00]

I keep geting a error when I try to start my Garry's mod server. It says:

Srcds.exe - entry Point Not Found
The procedure entry point
?CallWorker@CWorkerThread@@QAEHII_ NPAVCFunctor@@@Z could not be located in the dynamic link library tier0.dll.

I have no clue what this means or how to fix it plz help me

[mhorn00]

also if i click ok. it says:

There is no disk drive. Please insert a disk into drive
\Device\Harddisk1\DR1.