Only left audio channel active...

[herojoker]

Hello,

the following problems appears only at some of my .divx files and therefore I think it might be a problem within the files:
After opening the file xyz.divx only the left audio channel is active. This means the menu entry Audio > Audio channels > Left (I hope this is the right translation; I'm using the german version: there it is Audio > Audiokanäle > Links) is active. Setting it to Stereo is possible and definitely changes the sound playback (I can hear that it is real stereo after choosing Stereo).

In the IRC channel #videolan I got the tip that perhaps a tag is not set correctly: Dual mono instead of Stereo.
Do you know whether this is a bug or is it really an error in the files? If the latter is true, what could I do about it? Do you know a software to change the flag (without recoding the whole files; I think it should be possible by changing some bits, but I'm not an expert at this)?

The stream and media info dialog says the following about the file (I tried to translate it; removed unecessary information):

Stream 0:
Codec: DX50
Type: Video

Stream 1:
Codec: mpga
Type: Audio
Channels: 2
Sampling rate: 48000 Hz
Bit rate: 128 kb/s

Meta information:
Setting: HAS_INDEX IS_INTERLEAVED


Update: I've found the application GSpot which confirmed that the file contains 2 mono channels: GSpot says:
Codec: 0x0055 MPEG-1 Layer 3
Info: 48000Hz 128 kb/s tot , Two Mono Channels

Why is only the left one active by default?

I hope you can help me, thanks in advance and
Kind regards
herojoker