I spoke too fast...
kdenlive crashes immediately as I insert a clip in the time line...
I can't get it to work !
:(

Another 0.7.4 package in PPA worked perfectly for me on Jaunty 64 and is quite a nice experience all around. See this thread -

http://www.kdenlive.org/forum/kdenlive-074-launchpad-debs-jaunty-and-intrepid

I had the same problem, but it was solved when I realized I was trying to use SVN to update the mlt source code,
whereas I should have used "git pull" instead ;)