like I mentioned, when you compile a level, (level.wmp) for example, it will create several extentions in your project folder. such as -> WMB, $$M, $$p, $$w... You only need to concern yourself with the wmb file, as it is the file used to load the level through script.
where are your models placed? in a subfolder? if so you will need to have PRAGMA_PATH set up so te script can find those models.
Otherwise, you should take care to ensure everything is in the correct project folder, and that you didnt accidently save it to an arbitrary file, or location.
Ps. Thanks. Spent many hours on that tut

EDIT: Look into pragma path
