HL2 RunTimeError

[lister]

Hi, i haven;t played HL2 in a a few weeks, but ive been readin about sum new updates been released causing probs etc, but now i cannot play HL2, i get this error..
http://img.photobucket.com/albums/v647/lister8/runtimerror.jpg

 

[Beerdude26]

Tried validating?
steam://validate/220

Also, is your copy of HL2 up to date? (Does it automatically update?)