ok i fixed thee problem. while installing with faster appication installer the modules havent been set up. To do this manually I just reinstalled the packets. as there was another package missing i had to write those 2 commands here :

apt-get install --reinstall python2.5-qt4-webkit
apt-get install --reinstall python2.5-qt4-network

and then just

python /opt/cutetube/cutetube.py

to see if there are more errors. but there werent it starts now and i can see vids!