The NPO version is fine.
The cof import should not be any problem. Are you zipping it properly ?
I never had any problem importing the cof, as long as the format of the file is good, it should run smoothly.
Unfortunately, I can’t help you more than that : I can only encourage you to check your cof file one more time.
For the MIF, it can be more complicated, because the geo-coordinate system should be in long lat WGS84. If your initial ‘tab’ is in another format, it is difficult to translate it. You must first save your ‘tab’ using the “save as…”. And in the “save as” pop-up, look for “options” (or something like this) where you can actually transfmort the coordinates into the good system.
Then reopen the new tab and export it as .MIF.
Another thing you can do : send me your cof file and your mif, I can have a look 🙂