Engine.dll?

Fatal error

I used my original HL cd and i got it up and running in steam and everything seems to work fine, its just it seems whenever i use an attack i get a fatal error that says "MESSAGE_END called, but message buffer from .dll had overflowed"

thats question rather for valve/steam support...

are you trying this with bots?

if so, that is why, at the moment the open beta does not support the use of bots, they will crash the game. Bots will only be of use in 1.3.

Usually, you get that error while trying to play with bots. Bots don't work with the current open beta.