Well, I just got the Critical E097 as well. I simply added one map entity to my game. I tried deleting it out, but it did not fix the error. Interestingly enough, I deleted the building itself that the object was in, and the problem went away. The building was a simple 16 sided cylinder primitive with the center hollowed out via CSG subtract. I am running a 2.53 ghz pentium 4, so I don't think it's an issue with the computer itself.

Anyway I recreated the building and put it back in the map, and it worked just fine. I read in another thread somewhere that this error is supposed to go away in the next release. I hope so, it is indeed very frustrating.