I've got the following error message on Debian Linux (6.0) with Courier IMAP server:
Filesystem notification initialization error -- contact your mail administrator (check for configuration errors with the FAM/Gamin library)
when I tried to access a IMAP share. The resaon for the problem seems to be that the "fam" package was not working correctly. The solution is to install the gamin package which can replace fam in a courier setup:
apt-get install gamin
Dont worry when you get a message from apt that libfam0 gets uninstalled but is required by courier. This had no geative effects on my server.