Sorry dinosoep, I'm a bit dense sometimes.

You said you wanted to try openbox and now you have. You get a very nice grey screen on which you right click to get a menu. Lots of otherwise undiscovered applications but not the ones you love and no desktop - openbox is a window manger, not a desktop manager.

I realise now that what you meant was you wanted to try LXDE on openbox, the way it is meant to be, instead of on compiz.

The thread you refer to says something about a bug in 6.4.3 that's fixed in 6.4.4. You're still running 6.4.3. You may not deserve much tea and sympathy.

You should not need to uninstall compiz and I'd suggest that's a bad idea until you've actually got LXDE working on openbox.

A window manager is not quite on a par with your ordinary app. I don't think KK created Knoppix by simply installing a compiz package or two and uninstalling a few openbox packages. You might need to understand what KK did to replace openbox with compiz in the first place before you can replace compiz with openbox.

Luckily for you that may not be so hard. Have a look in /etc/X11/xsession.d/45knoppix.