Sorry munozferna if I'm replying so late, installing qt-components-10 did the trick on my N900, I don't know if they were a dependency or not but I had to apt-get the package manually.
Anyway, today I updated the application to 0.4 and it seems to run much more stable, 0.3 was crashing all the time, expecially when minimized.
Your app is great, being able to load my preferred mixes would be a must, I hope that someday you will be able to implement the user profiles function.
Thank you again!