Posted by Grega:
i advise you to devirutise/deaddware/despyware your PC.
Ahh, the three D's of PC health, words to live by.
Grega is absolutely right.
But, if you try this and it does not work, are you redownloading the file from the same server?
It could be corrupt there. Which server did you download from.
If you haven't tried, use:
http://www.esf-world.de/
you'll find everything you could possibly need there.
I've found that files on some of the other half-life mod sites, that the mirrors usually have outdated or corrupted files.
I hope this helps.