After running "addebug on" on a SUSE Linux with SP2 the centrifydc.log and centrify_client.log do not grow an remain at zero.
ryslogd service is used to append those log files, the service can become stopped on this OS.
Check if rsyslogd is running. If it is not running please start/restart the service. After starting/restarting the service please toggle addebug off/addebug on.