Thanks for your quick reply and for looking into it.

The clincher is that if you save to .map format in 3D Game Studio all of the entities are saved in the file too (you can see them using notepad) but when you load the file back INTO 3D Game Studio, they don't get loaded right and show up with a question mark in the explorer.
I guess people don't use .map's very often so this got overlooked, I just wonder if there is any way around it.
I could always just export to wmp format but I've read in a few places that it changes from version to version, so I'd rather stick with the .map format if possible.