OK, then does these files work on another program, like VLC, or Handbrake?
Since you have a
thread on the Bleeping Computer forum also, it looks like you are trying to do some editing of the files, which I think Handbrake can do.
Also in that forum, you were asked if you have the paid license version, but you did not confirm, just that you had a premium copy, which could mean you have an unlicensed version. If you truly paid for a license, then you really should be contacting their support since you paid for the software... If you have a trial version, then that is not a full version; it will have limitations, which is what you probably are seeing right now.
Edit: I misread that as in you have
not used it before. So to confirm, are you able to use past files that has worked before?