Hello Julius,
The current available CUPS Patch Installer for QuarkXPress is not compatible with Leopard. The reason it is failing on the post-flight check is that after installation, we try and force-quit CUPS to have the changes take effect. In Tiger, CUPS was always running but in Leopard, it isn't. So, the installation was actually successful but the CUPS restart is failing. This is something we are working on.
As for the problem you are having, it appears to be bigger than our CUPS Patch as Adobe Acrobat is not compatible with Leopard. Adobe has stated they will be releasing an update sometime in Jan 2008. I have seen many posts about this exact issue in the Adobe forums which you can find
here.As for the Courier issue... I have not heard of that problem and could not reproduce it on my machine (10.5.1 US English). My recommendation is to use our Direct PDF Export until Adobe releases an official update to Acrobat for Leopard. As someone who came from a production environment and used to rely on Distiller, I can honestly say that our Direct Export is greatly improved and see less and less of a need for Distiller.
Hope this helps.