Project monitor hangs with overlapping video tracks

Hello,
I have an issue that prevents me from being able to work with kdenlive. I load two video clips and put them on separate tracks, without any additional effects of any kind. If the tracks overlap, then the preview monitor will always hang as soon as the first track ends, i.e. at the ^ in
[ Track 1 ]
[ Track 2 ]
^

If the tracks do not overlap, the project monitor does not hang.

It does not matter what type of video clips I use. After the hang, when I close the program (which usually is still responsive as long as I do not start fiddling around with the already hung project monitor), the kdenlive process keeps running even if no windows is visible anymore. If I try to render the project (even without playing the preview in the project monitor before), the rendering process will hang at a percentage that appears to exactly correspond to the above shown spot.
Running on Fedora 12 x86_64 on GNOME, using latest version 0.7.7.1. Tried setting audio output to alsa instead of automatic, killing the pulseaudio daemon, using videos with no audio track, but issue always persists. Any help would be greatly appreciated.

Cheers,
smani

uhm.. spaces got cut...
[ track 1 ]
........[ track 2 ]
...............^

Does it also get stuck if you start playing from where the first clip already ended?
[ track 1 ]
........[ track 2 ]
................^

And what happens if you use audio files? (for example mp3s)

Also make sure you use the latest version of mlt (0.5.2)

Thanks for your reply.
Playing after first clip ended: random results: first time it simply displayed a white screen but did not hang, second time it actually played a few frames of the second clip and then hung.

Audio tracks: that specific problem does not appear, although it hung up a few seconds after the transition.

MLT is the latest version, also tried compiling directly from git.
I have opened a bugreport concerning the issue at http://www.kdenlive.org/mantis/view.php?id=1553