Weapon Textures Suddenly gone!

Just last night I was playing Black Mesa up to the end of the “Questionable Ethics” Chapter and everything was working just fine. I left from there, rejoined the game this morning and suddenly, ALL my weapons textures have changed to the purple and black checkerboard (missing textures). I checked the game files and the weapon texture files are all still there. The only thing I did between last night and this morning was verify my integrity for Source SDK Base 2007, and I also put ‘-dxlevel 9.0’ in the Set Launch Options for Black Mesa. Did doing any of those REALLY cause my weapons to lose their textures?!?!?!