Switch won't convert m4a to mp3

[duneworld]

Hello.

I downloaded a free trial of Switch (version 1.31) on the 24th December, it is currently in the 14 day trial period and will be for another 13 days. I tried to convert an m4a file to mp3 @ 160 kbps. The input files are only about 5 MB. The reason it states that it wont convert the file is: "The specified source format could not be read."

This doesnt make any sense to me because I had a previous version: Switch Plus v1.05 full, and this would have had no problem converting these files. I would have kept this old version if I had known that I would have such trouble with a newer version, unfortunately I cant seem to get the old version to convert files anymore.

Thanks for any help, Dune.