/dev/hdb1 /mnt/hdb1 etc defaults 0 0
And your hdb1 partition type?Is it vfat, ntfs, ext2, ext3......etc?
Check with : fdisk -l
Try put it at the bottom of yout fstab and add "auto" in that line.

EX. if hdb1 is a vfat partition:

------------------------------------- beginning of file
# /etc/fstab: filesystem table.
#
# filesystem mountpoint type options dump pass
/dev/hda1 / ext3 defaults,errors=remount-ro 0 1

proc /proc proc defaults 0 0
/dev/fd0 /floppy vfat defaults,user,noauto,showexec,umask=022 0 0
usbdevfs /proc/bus/usb usbdevfs defaults 0 0
sysfs /sys sysfs defaults 0 0
/dev/cdrom /cdrom iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/cdrom1 /cdrom1 iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/dvd /dvd iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/cdaudio /cdaudio iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/cdrom1 /mnt/auto/cdrom1 auto users,noauto,exec,ro 0 0

# Added by KNOPPIX
/dev/hda2 none swap defaults 0 0
/dev/hdb1 /mnt/hdb1 vfat auto users,exec,umask=000,quiet 0 0

------------------ end of file contents