cups probelm “client-error not possible’

Is one of those “self-speaking” error messages. If you run into this while printing from bash with ls -la | lp -d or while trying to print a test page from the CUPS Webinterface you should check the content of your CUPS spool directory /var/spool/cups. In most cases you’ll find a lot of files in there. You can move them away or delete them. After that you simply have to restart the CUPS Service with /etc/init.d/cups restart