the models won't export.

Yes, of course, but then why do I still get the same error when I try to export an existing model, even with the correct version of the .dll?

Doesn't my manual state that this method allows you to export models that already exist in the game (and are displayed in the editor)?!

Check my instructions again, step by step – if you are using my test model correctly, it should be successfully exported from the .mb format to the game engine format (so-called .niv – the extension is not displayed). However, it is also possible that this file has become corrupted! Try downloading it again!