If you give me a link to the file, I can try a conversion.
Also, it would be wise to make ToT versions of all the GFX files (terrain/icons/cities) beforehand.
Having many things in place will make life easier, for when you load the converted file.
Keep in mind that there are a few minor differences between MGE and ToT files...
It would pay to get familiar with the nature of them, before you dive in.