"Node graph out dated: Rebuilding" and "AI Disabled" Errors!

[}SkOrPn--']

Hello, noob here.

I just started getting this error "Node graph out dated: Rebuilding" and then the game starts and "AI Disabled" is listed on the screen and characters dont move. Game cannot be played without AI. It goes away only if I start a new game but once I have to save it and restart the game the error is there again and no characters move anymore.

As it is Half Life 2 is useless to me now. I use steam only and also own HL2 Lost Coast and Episode One. It does NOT happen in Loast Coast so far and Have not tried Episode one yet but I havnt played HL2 yet either so not willing to go into Episode One just yet. lol

Should I delete everything and re-download steam and all game content again? and maybe re-install Windows and latest drivers. All drivers are the very latest.

Asus P5B Deluxe
Core 2 Duo E6700
2 Gig DDR2 Memory
8800GTX all stock settings
ForceWare Version: 158.22
Release Date: May 16, 2007
WHQL Certified
Windows XP x64 SP2

Any help would be appreciated thanks.

 

[Mahalis]

Validate HL2. Right-click it in Steam, select "Properties", go to the "Local files" tab, and click "Verify integrity of game cache...".

 

[}SkOrPn--']

Done that several times allready and I even defragmented them. Will try a third time real quick though.

Thanks for reply.

 

[}SkOrPn--']

Ok just Validated a 3rd time and re-defragmented a 2nd time, still same errors and NO AI at all.

Is it possible that old game data backup is no longer valid or something? The backup of HL2 is about 1 and a half years old, but Windows is only a month old or so. I installed the latest steam, then did the normal backup install routine, restarted steam and all was fine. This was done yesterday and HL2 worked just fine, but today it has this error and I cannot play the game.

Is this not a very well known error with a easy fix?

 

[Mahalis]

It's well-known, but it's usually caused by a pirated copy of the game. That doesn't seem to be the case here, so yeah, I'd suggest "Delete local content"'ing HL2 and re-downloading it.
Actually, to be on the safe side, delete the shared stuff as well - go to your c:\program files\steam\steamapps folder and delete the source materials, source sounds, source models, sourceinit, source engine, and base source engine 2 GCFs.