The file movie.avi is not a valid video file for kdenlive

Hi,
First, thanks for a really great product.

Second, I had kdenlive 0.6 from

http://3v1n0.tuxfamily.org

working ok last week on kubuntu 7.04. I had to get libfree6 and its dependencies from the gutsy repo, but in the end it was working.

Third, I have now upgraded to kubuntu 7.10 and installed kdenlive 0.5 from the gutsy repo. I now find that I am unable to add any clips to a project. I have tried adding w32codecs, mencoder, and some other things that I cant remember right now. The clips are the same ones I was able to add last week using 0.6 on fiesty. I have tried adding .avi .mpg .vob files and none of them work now. I get the error

The file movie.avi is not a valid video file for kdenlive

I did a search but was unable to find any help for myself, so I'm asking for your help.

Thanks.