umount filesystems crach...

[MG]

Hi!

Sometimes when I shutdown the system, then crach the linux. I have to reset the
machine. :(
The shutdown process freezes at umount filesystems. Why?

The "/etc/fstab":
LABEL=/                 /                       ext3    defaults        1 1
none                    /dev/pts                devpts  gid=5,mode=620  0 0
none                    /proc                   proc    defaults        0 0
none                    /dev/shm                tmpfs   defaults        0 0
/dev/hda3               swap                    swap    defaults        0 0
/dev/cdrom              /mnt/cdrom              udf,iso9660
noauto,owner,kudzu,ro 0 0
/dev/fd0                /mnt/floppy             auto   
noauto,user,uid=500,showexec 0 0
/dev/hda4               /mnt/hda4               vfat   
auto,user,uid=500,showexec 0 0
/dev/hdc1               /mnt/hdc1               vfat   
auto,user,uid=500,showexec 0 0
/dev/hdc2               /mnt/hdc2               ext3    auto 1 1
/dev/hdd1               /mnt/hdd1               ext3    noauto 0 0
/dev/cdrw               /mnt/cdrw               iso9660
noauto,user,uid=500,ro,showexec 0 0
/dev/fd0                /mnt/floppy             auto   
noauto,user,uid=500,showexec 0 0
/dev/scd0               /mnt/scd0               iso9660
noauto,user,uid=500,showexec 0 0
/dev/scd1               /mnt/scd1               iso9660
noauto,user,uid=500,showexec 0 0
/dev/sda4               /mnt/usb                vfat   
noauto,user,uid=500,showexec 0 0
maros.intranet.domain.hu:/NEWDATA    /mnt/nfs/NEWDATA        nfs    
noauto,bg       0
maros.intranet.domain.hu:/NEWAPPS    /mnt/nfs/NEWAPPS        nfs    
noauto,bg       0
maros.intranet.domain.hu:/NEWHOME    /mnt/nfs/NEWHOME        nfs    
noauto,bg       0
host004.intranet.domain.hu:/usr/local/utils/nfs      /mnt/localnfs   nfs    
noauto,bg       0


Bye!
Gabor