If a map doesn't load in the game...

[JLukas]

...but looks correct in TF, double check your map properties.

L3 Tileset should be $FF for maps that don't use L3, and the setting Draw L3 should be False.  Incorrect settings for the other options can likely causes problems as well - when in doubt, check a similar map that wasn't modified.

[Agent 12]

Hurray!

I was really worried it had corrupted.  Thanks for the heads up.  Just to clarify does exporting a Location Map in TF export the map properties to?

--JP

[JLukas]

Everything in the Map Properties window, yes.  The L3 Tileset $FF setting mentioned above is in the Location Properties window, however, and will need to be set manually.