autofs prints "automount[19165]: syntax error in nsswitch config near [ syntax error ] " to syslog

autofs prints " automount[19165]: syntax error in nsswitch config near [ syntax error ]" to syslog while started. Within /etc/nsswitch.conf I have:
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.

passwd: compat
group: compat
shadow: compat

hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
networks: files

protocols: db files
services: db files
ethers: db files
rpc: db files

netgroup: nis

As far as I see there is no syntax error within nsswitch! What ever this error message means: autofs doesn't work as expected:

/etc/auto.master:
/media/cifs /etc/auto.cifs

/etc/auto.cifs:
box -fstype=cifs,rw,credentials=/etc/fritz.cred ://192.168.6.1/FRITZ.NAS

Changing to /media/box:
# cd /media/box
bash: cd: /media/box: No such file or directory

While
# mkdir /media/box
# mount -t cifs -o rw,credentials=/etc/fritz.cred //192.168.6.1/FRITZ.NAS /media/box

works (if autofs was terminated before. Else you'll get the error: "mkdir: cannot create directory `box': Permission denied"):
# ll /media/box
total 4.0K
drwxrwxrwx 3 tps tps 0 Jan 1 1970 ./
drwxr-xr-x 3 root root 4.0K Jun 21 16:26 ../
drwxrwxrwx 9 tps tps 0 May 28 60056 PatriotMemory-01/

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: autofs (not installed)
Uname: Linux 3.4.3 x86_64
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Thu Jun 21 16:06:26 2012
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
ProcEnviron:
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: autofs5
UpgradeStatus: No upgrade log present (probably fresh install)