"Error" inside Half life 2: EP1

[nfamous]

Both Half life 2: ep 1 & lost coast have big "error" signs displayed randomly throughout the levels. I've searched google, steam, and here, and haven't found anything. How can i stop those signs from being shown? I'm running both @ 1680 x 1050 with 4x aa, hrd, and AF at different levels.

Relevant system specs:

Opty 165 @ 2.2 ghz
1 gb ram
36 gb raptor
x1800 GTO w/ a slight overclock