Codec required could not be opened

[Vispon]

Can someone please help me with this a friend recomended this program for converting audio files however whenever i try to convert to Mp3 i get "the CODEC required to compress 'D:\MKVExtractGUI-mkvtoolnix-WinXP2K\Track2.mp3.TEMP.mp3' could not be opened." If i try to compress to wave all I get is 'program has encountered an error and has to close". I've tried reinstalling but to no avail. I was in the middle of a set of instructions on how to reincode video so this is really annoying. at the time i was encoding from aac and the codecs are deffinutely installed. Any ideas?

[xoas]

What types of files were you trying to convert?
What is their format, frequency, bitrate, number of channels;
What mp3 settings are you trying to convert to?

[ChristinaS]

Don't forget, you need a registered or unpexpired trial version of dMC in order to encode to mp3.

[LtData]

If your still in the trial version of dMC, try the latest dMC beta linked below. It's more tolerant when compressing mp3s.