Well, I was mapping a recenlty edited map, added all my textures and such. Cleaned and munged as always, booted it up, and nothing worked.
Sptest tells me that it cannot read the .lvl. I clean and munge again, and it still fails. After hours of tweaking and debugging, even recreating the entire map, I still have this problem. As it turns out, the problem was that the .lvl file was never being created. However, how do you fix such an error, even after creating a new project?