NCF – Extended list of Neutral creatures.

It seems like there's something wrong with your game. Is it a pirated copy, by any chance?

Everything is fine with the game. The bug with the Stalkers is well-known. I had it too.

Added 3 minutes later
You've messed something up. You've added something to the data archive, which is ideally protected against such modifications. Why? Have you tried replacing the creature file of the Stalkers mod with a similar file from the new version? The problem lies in the ability. Something isn't properly defined.

Added 30 seconds later
And it was fixed in the new version.

Added 1 minute later
And yes, you can't delete creature files from the archive. This causes lags in all files that reference this creature.