This is what WC3 does when the model is impossible to draw on screen. In other words, you messed up. For me personally, common causes of this are refering to textures that don't exist in a given map (ie, custom textures I forgot to import) or texture*ID* references that are incorrect.
If you were editing the geosets, I'd say your mistake lies there. Worst case scenario, you may want to start again from scratch, and perfeorm one editing step at a time until you isolate the one causing you the error. | 
