Hi ,I will try to help
please can you import the clips via the File menu import instead of drag and drop .
There maybe bug in the drag and drop action .
If this does not work , what is the audio format of the audio? 12bit can cause issues in all OSX apps , 16bit or 24bit is the norm for OSX . 16bit 48khz is a good choice .
The application above linked can import and convert video files with multi channel audio such as MKV with AC3 and .vob DVD files. This could help also with the import .
Mpeg stream clip is also a good converter and is free . I cant speculate if the multichannel audio will work without trying on your particular video file , but it is again worth a try .
You can convert the video to other formats before importing in to FCP.
What is the audio format of the video file , this info can be found in Get info via finder . or in Quicktime see properties of the Video file's audio etc.
Found the problem.......The downmix button was depressed on the audio mixer.........What an idiot!!!
LOL, well that can effect the problem .
I found this last night ,
MKV tools , may come in hady if you dont have these , this was updated from the last MKV tool , has more options and seems well with 10.6.4 ..
I guess your all fixed up .