Weird compiler error code

Anyone have seen this error before? classID >= ms_MaxClassID || classID < 0

When I run the game, I dont see any errors in runtime, but the compiler still shows the error. What causes this error?

My group had this issue for over 8 builds and we still didn't know where it was originating from until we deleted all of our scripts. The problem was that a variable passed into a function was data-typed wrong. We accidentally used the function OnControllerColliderHit() and passed in the variable hit which was data-typed to Collider. The problem is that it was supposed to be data-typed to ControllerColliderHit.

The function is probably different, but your issue is probably similar.