Rendering produces broken audio

I installed Kdenlive in Ubuntu 10.04 and works very good. I did an additional installation, but in Ubuntu 10.10 and I get a couple of problems. The codec to render in WMV get an error: unsupported audio codec (but it is supported in my Ubuntu 10.04 installation!). Additionally, when I render in Apple QuickTime the result produces low, broken audio with echo. That doesn't happens on Ubuntu 10.04. What should I do to fix it? Thanks.

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