Ran in to a problem a bit weird with few info on it on the web.
It's seems like a bug in KDEprint
If ever you notice you can't print from any KDE apps anymore and encounter the following error message:
Error message received from system
Error while reading filter description for true
Empty command line received
I have found the soltution. A filter called TRUE is being created in a unknown fashion. It needs to be deleted in the printer properties filter tab.
Tought I would share.