Need help adding a song to a video

[Ragnarox]

I've been trying to add a song to the background of one of my videos by using the Secondary Audio Track option to put in an external file, but whenever I try to load the song, I get an error message that simply says "Error loading the MP3 file." I've tried this with the video in multiple formats- AVI, AVI with dual audio, MPEG, MP4, etc, and I get the same error every time. I tried using a WAV file instead of the MP3, and that time, it said "Second track loaded," but the song was not at all audible in the video. Any help with this would be appreciated 

[Jan Gruuthuse]

Avidemux wiki documentation: Dual audio:

Restrictions
The second audio track must be CBR, that is MP3 CBR or AC3. It only works when the output format is ââ,¬Å"AVI, dual audioââ,¬Â.

1st upgrade to 2.5.6 for your OS, if you don't have this one.
2nd make sure the mp3 is CBR and not VBR
VLC will allow you to choose 1st or 2nd audio track to play while viewing the video.
If you want to play 1st track and 2 track simultaneous when playing the video, you need to mix/join track1 with track2. This can be done with programs like audacity.
With this program you can also make your mp3 CBR instead of VBR.
Download links to sample MP3 and avi with second audio channel added.
MP3 CBR short: 0.7 MB https://rapidshare.com/files/4004885570/CBRshort.mp3
Dual Track AVI:  32 MB https://rapidshare.com/files/1132056569/dualtrack.avi
Audacity is available for WindowsÃ,®, MacÃ,®, GNU/LinuxÃ,®, and other operating systems