This is related to some other issued I've had with my level...

In any case, if I build my level (which has many entities) and "preview" it, it looks fine--all entities and blocks and models are there, all textures appear as they should, etc. When I "run" the level, again, everything looks normal as long as I don't have a script attached to the level (as determined in the MAP properties). As soon as I attach a script, however (among others, I tried the "walkthrough" template script), most of my entities and blocks don't show and most of the level is black; I can move the camera, but it is extremely sluggish. My level/world is rather large and complex with many items, but I don't get any errors telling me that there are too many.

Can anyone tell me what might cause this to happen?

And is there a way to essentially duplicate the level "preview" mode with a script (because that at least works).

Thanks.