logger watches the logs and gathers stats - it's completely optional.
There's a fixperms.sh script that will fix any permission errors you created by starting tomcat as root - it's in /opt/zimbra/libexec, I think.
Thanks so much. Running the script has fixed my logger problem. Is it likely that starting Tomcat as root was the cause of all my problems? And is running /opt/zimbra/bin/tomcat stop then start the correct procedure for restarting tomcat?
Also...for others who may run into this the script may be found at /opt/zimbra/bin/zmfixperms.sh.
Thanks a load, you guys are truly the best.
In general, it's best to use either zmcontrol or zm<service>ctl to stop/start things. For instance, zmmailboxctl handles both tomcat and sql, in the correct order, so if they're both wedged, you'll want to use that. In this case, tho, tomcat alone was the problem.