Initially, the computer was showing the error as mentioned in How to fix "The system is running in low-graphics mode" error? question. Fixing it resulted in the above error.
Please take look at the last line
Started GNOME display manager... and deal with any system changes..p link was shut down.....
One more thing before all this problem I have edited xorg.conf file to use Tooya X graphic tablet as suggested on here.
I don't know if that's the reason but I thought it is important to share.