If it's like mib2 high which it will be you need the navigation FeCs for your region they are different to European ones I reckon. But then where you say no update files found I don't think you present them as a "update" it just finds them. On those pdfs I put on the first post on mib3 offline map updates. So it's probably not "update" as a menu option.
Now I'm not too sure whether Audi dropped their mapcare
service or whether they want you to pay. If so your navigation FeCs wouldn't be life long but truncated to a time period. Then we have the mystery of what maps your unit takes. We know Audi have some esoteric units. Mib helper may give you some
help on what it's expecting your unit to take.
The other thing is to try a different historic map. Presentation is all important with these map files so if not unzipped correctly it won't pass the validation.
If you got a retrofitter to do it for you they might not have done the activation correctly. So it's finding that Audi navigation fec and seeing whether it's life time. This revolves around what deal Audi have as I touched on above. Seat, Cupra and Skoda scrapped mapcare and allow uploaded maps for free. Check the Audi site. You should find on the net a decode for the Navigation FeC. I mutter this since an unscrupulous retrofitter was selling map updates / software updates for mib2 highs that only gave you 12 months. Good for repeat business.
A few pointers.
I'll check to see what your third line down on the screen is saying.