autofs5 install error (no replies)

Hello,
I'm trying to get a USB auto mount function on a Pogoplug Pro (Oxnas) with Debian Squeeze. This is how I ran the command:

apt-get install autofs5

It seems to install ok until it gets to this step at the end:

Setting up autofs5 (5.0.4-3.2) ...

Creating config file /etc/auto.master with new version

Creating config file /etc/auto.net with new version

Creating config file /etc/auto.misc with new version

Creating config file /etc/auto.smb with new version

Creating config file /etc/default/autofs with new version
Starting automount: Error: failed to load autofs4 module.
invoke-rc.d: initscript autofs, action "start" failed.
dpkg: error processing autofs5 (--configure):
 subprocess installed post-installation script returned error exit status 1
configured to not write apport reports
                                      Errors were encountered while processing:
 autofs5
E: Sub-process /usr/bin/dpkg returned an error code (1)

I'm not sure what the "failed to laod autofs4 module" means. Do I have to install autofs4 first?

Thanks,
Eric