Kubuntu - KDE - Unable to log in and work around

PROBLEM DESCRIPTION:
While playing around with my Kubuntu installation, I stopped some services thinking that will make my system's startup faster... but what happened was - the boot process completed successfully and showed me GUI login screen. When I entered the username and password, the screen went blank for a few seconds and then the login screen appeared again.

DIAGNOSIS:
Just to see what was going on, I shifted to console based login. Upon entering the username and password there, the screen was flooded with the following message
-bash: /dev/null - Permission denied

WORKAROUND:
A simple
sudo chmod a+rw /dev/null
and then
startx
started everything normally.

IT AINT OVER YET:
Upon restarting the system, the same problem reappeared indicating that the permissions had been reset.

WORKAROUND:
chmod a+rw /dev/null was added to /etc/rc.local before
exit 0 (which was already written in the file)

DEEPER DIAGNOSIS:
I called one of my friends, a Red Hat certified professional. He explained me all the fundas of runlevels and how things are done in Red Hat. As a part of diagnosis, we shifted to runlevel 5 (current workaround i am using) and everything was working fine. A comparison of services didnt yield much as we found out that udev and MAKEDEV were present in both the levels, which according to us were responsible for dealing with permissions/creation of /etc/null.

I BELIEVE ITS JUST A QUICK FIX THING THAT WE HAVE DONE AND IT IS NOT A PROPER SOLUTION, THEREFORE I HAVE USED WORKAROUND AND NOT SOLUTION EVERYWHERE IN THIS POST. IF ANYONE COMES UP WITH A SOLUTION, THEN PLEASE POST IT IN COMMENTS. THANKS

FINAL WORKAROUND I AM USING:
Shifting to runlevel 5 by editing /etc/inittab -

Original /etc/inittab (first 4 lines only)

# /etc/inittab: init(8) configuration.
# $Id: inittab,v 1.91 2002/01/25 13:35:21 miquels Exp $

# The default runlevel.
id:2:initdefault:

Modified /etc/inittab

# /etc/inittab: init(8) configuration.
# $Id: inittab,v 1.91 2002/01/25 13:35:21 miquels Exp $

# The default runlevel.
id:5:initdefault:

This workaround didnt require editing rc.local.

Regards,
Dev