I'm guessing it doesn't like the separate Frequency Input and Output columns... but I've imported CSVs from RR before without issue, surely CHIRP knows how to handle these columns? I must be missing something simple, if this were a major problem you'd think I'd be able to find something in searching this forum, but a forum-wide search of "chirp unknown file format" returns zero results.
Matt,
Its been awhile since I imported from RR database and I know some items can be excluded. Maybe input frequency is one, but don't know. If available open the file in excel for easy removal of that column. It possible the file includes columns chirp does not know about and gives up.
Input parsing of a file is always a crapshoot if it will works well or works at all.
Another approach is open the file in a simple editor, copy and paste a few lines into another blank file. In that new file with limited data its easy to change to figure out if you can get it to load.
Also, read the radio with chirp and export the data to a csv file. That file will have header naming and order convention the input should have.
I'm not a chirp user so some of what I suggested may help, or not.
Good Luck,
Mike