Originally Posted by Saturn

This comes from a problem in the Qt libraries happened a few weeks ago in the repositories. In short, a development version has been wrongly pushed to extras.
It has been fixed in the repositories but the fix cannot be propagated automatically in the N900s affected.

So you need to update your qt4 libraries manually to fix this.
Switch off the devel repo and use the testing repo.

Can you post the output of your:

Code:

dpkg -l *qt4*
dpkg -l python2.5-*

as well as:

Code:

root
apt-get update
apt-get -s upgrade