[cups.general] Centralized Server Problem

[Caspar Siebeneicher]

Hello again,
I downloaded and installed ppf but I am unable to get it to work. Maybe
it has something to do with my printer device on the client.
/dev/usblp0
in the syslog it says 
Unable to open '/dev/usblp0' due to: Invalid argument
webUI says '/usr/lib/cups/backend/socket failed' (guess thats normal when ppf's not running well)

The printer is connected and the cable not broken ('cat testpage.ps |sudo tee /dev/usblp0' prints my testpage)
I already tried:
-creating a symlink /dev/usb/lp0 -> /dev/usblp0
-changing a variable in source from /dev/usb/lp0 to /dev/usblp0 and recompiling (a desperate try...)

The client is running ubuntu 7.04. Do you have any hint in which direction to search (google wasnt very helpful)?

And does this (use of ppf) mean that it is not possible to do what I want with CUPS ?
Thank you for the time already invested!
Greetings,
Caspar