[FIX]cannot lock media/.hal-mtab Error
if you are trying to attach mass storage device(USB) or DVD Drive or Windows Partition then it won't automount it and instead will return an error citing "cannot lock media/.hal-mtab" .while try to access the device.here is quick fix-
make a directory mkdir /mnt/sdb1 #sdb1 is for Pen drive,change it with the desired partition like /hda or /sda1,/sda2 etc.
mkdir /mnt/sr0 #for mounting DVD/CD Drive
add the USB device/HDD Partition/DVD/CD entries to /etc/fstab
for example if its sdb1 it should look like
/dev/sdb1 /mnt/sdb1 vfat auto,noatime,users,suid,dev,exec 0 0 #Autoupdate
change vfat & /dev/sdb1 with the format e.g ntfs-3g etc & corresponding file system.
Read my tutorial on Dual Boot BT4 with Windows and there I have mentioned how to mount different partitions including NTFS-3g,vfat etc.