Problems with autofs and .hidden files

Hello!

We are using autofs in order to mount the user's home drive via NFS after a
successfull login authenticated by ldap.

/etc/auto.master looks like this:

# AUOTOFS-MAPPING
/home/schueler Â*/etc/auto.schueler
/home/lehrer Â* Â*/etc/auto.lehrer
/home/maerkte Â* /etc/auto.maerkte

/etc/auto.schueler has the following content (the same also applies for the
other files):

* Â* Â* Â* -fstype=nfs,rw,hard,intr,nodev,nosuid,exec,acl Â* Â* Â* Â*
server.domain.de:/home/schueler/&

Generally speaking this setup works like a charm but from time to time we
encounter the following messages in syslog:

Sep 24 16:46:57 server mountd[8818]: authenticated mount request from
client.domain.de:559 for /home/schueler/.directory (/home/schueler)
Sep 24 16:46:57 server mountd[8818]: can't stat exported
dir /home/schueler/.directory: No such file or directory

Our investigations show that these messages are probably to be created
whenever a user tries to access /home/schueler by using Konqueror or
Nautilus. The file .directory doesn't exist, however, and that's why these
messages appaer. Normalley, this wouldn't be a severe problem but the
entire is completely slowed down so that another kind of error occurs:

Sep 24 16:47:00 server mountd[8818]: refused mount request from
client.domain.de for /home/schueler/.directory (/home/schueler): illegal
port 48337

Does anybody know this issue and could provide any hints how to solve it?

Cheers,
Fabian