Can’t help you much, but wanted to point out that there is 1 not yet completely resolved bug report about this:
#578937 – courier-base: Emits “Filesystem notification initialization error” to client software

Alan Chandler reported that he uninstalled libfam0 and installed libgamin0 instead.

Maybe you should purge libfam0. And make sure you restarted your imapd.

Andreas Schamanek