package gdm 2.30.2.is.2.30.0-0ubuntu5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Saji Nediyanchath]

Binary package hint: gdm

My upgrade was incomplete due to this error. I'm now attempting to fix it, as it may have been caused by the lack of space in my hard-disk.
Also the installation of MySQL-server-5.1 package(upgrade) took a long time with no progress, so I killed the Update window using 'xkill' then when I tried to run update again. It showed some error related to unavailability of 'lock' at /var/lib/dpkg/

So, I remove that file by using sudo rm. Then the update manager suggested to fix the broken updates first by running-
sudo dpkg --configure -a

So, I did that. Also it suggested me to do-
sudo apt-get install -f

I did that as well.
After that I ran the upgrade and atb the end of it I got the message(posting only the last part)-
'
Errors were encountered while processing:
 gdm
 man-db
 linux-headers-2.6.32-29-generic
 flashplugin-installer
 opera
 mysql-server-5.1
 linux-headers-generic
 mysql-server
'

ProblemType: Package
DistroRelease: Ubuntu 10.04
Package: gdm 2.30.2.is.2.30.0-0ubuntu5
ProcVersionSignature: Ubuntu 2.6.32-28.55-generic 2.6.32.27+drm33.12
Uname: Linux 2.6.32-28-generic i686
NonfreeKernelModules: wl
Architecture: i386
Date: Sat Feb 12 12:03:55 2011
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Beta i386 (20100406.1)
SourcePackage: gdm
Title: package gdm 2.30.2.is.2.30.0-0ubuntu5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Saji Nediyanchath (saji89)]

I freed up space in my laptop, restarted the computer and ran-
sudo apt-get install -f

The Update was completed and package gdm was updated correctly. I think that the problem was with the lack of space. The downloaded update files was nearly <165MB( since, I haven't run the updates lately). I had only nearly 400-500MB remaining in my hard-disk, it didn't occur to me that to install all the packages when uncompressed it may take up more space.
It would be nice if some sort of error message is included while updating/upgrading to warn the user of low-disk space, for the sake of newbies.

[Saji Nediyanchath (saji89)]

Since this was actually caused due to my fault(low disk-space), I'm converting this into a question.