automounter problems

I have a Buffalotech NAS device on my home network with a series of SMB filesystems on it. All user home directories are on these filesystems. I use the automounter to mount the correct user's home directory when they log into the Mac. I'm running Snow Leopards on all the Macs on the network. Intermittently the mount gets done by root or switches to root ownership and the user can't access the files on the mount point. The only solution I've found is by manually going in as root, umounting the mount point, chown the mount point back to the user and then everything is fine. Why is this seemingly random and intermittent change to root happening? Has anyone else seen this? Is there any solution other than what I've described?

Thanks

Enis