Firstly, may I suggest you change your log-in name to something else than your email address. These forums are scanned by all sorts of 'bots which harvest addresses, and I would hate to see yours harvested and sold to someone who will pester you with lots of spam emails.
Videowave in NXT 7 claims to deal with .MTS files, and a large number of other formats. Here is the file input area . . .
Since I don't have any .MTS files to test with, would you please attach one or two small ones (just a couple of seconds will do) to a reply, so that I can test that Videowave itself is faulty and not just something wrong with your machine?