I read the Linux+FreeBSD--MINI-Howto and followed the instructions to mount the bsd partitions but I couldn't,though they share the same swap partition.

This is a quote from dmesg:
Partition check:
hda: hda1 hda2 hda3 hda4
hda3: <bsd: hda5 hda6 hda7 >

-Details:
hda1--> slackware
hda2--> /home
hda3--> freebsd
hda4--> redhat
hda5--> ROOT of bsd
hda6--> swap
hda7--> /home of bsd

-The command which I tried to mount bsd partitions:
#mount -t ufs -o ufstype=44bsd /dev/hda5 /mnt/mount-point
-The error message:
mount: wrong fs type, bad option, bad superblock on /dev/hda5,
or too many mounted file systems

-Notes:
-ufs is loaded as module--via modprobe ufs
-tried to mount it under both slackware & redhat still have the same problem.

could anyone enlighten me?

Thanks in advance..

I believe fbsd now uses ffs. no longer ufs.
don't know about linux support for ffs.