You might have been facing the error getting logged in /var/log/messages. Deeper research in Google gave the result that it is the issue with the loaded Kernel.

Before going for and upgrade, just confirm the following.

Check whether the following files are present.

/lib/modules/*/modules.*map      depmod output
/proc/sys/kernel/hotplug         specifies hotplug program path
/sbin/hotplug                    hotplug program (default path name)
/etc/hotplug/*                   hotplug files
/etc/hotplug/NAME.agent          hotplug subsystem-specific agents
/etc/hotplug/NAME*               subsystem-specific files, for agents
/etc/hotplug/usb/                   depmod data for user-mode drivers

chmod 755 /etc/hotplug/*.agent
check tail -f /var/log/messages

Now try the following before kernel upgrade.

The issue should have been fixed by now. If the message is still coming up in /var/log/messages, you will need to go for Kernel upgrade.

Thank you guys..

I am not sure why did the Ubuntu guys…left out the wvdial package in the latest distributions. In fact, most of the 3G wireless internet connection uses the PPP connection using wvdial. To install wvdial package, you need install some dependencies also.
After some research, I have found out the exact packages and the order to install them. Here are the steps to install wvdial for Ubuntu. You need to download the packages to a thumbdrive so as to copy it to the Ubuntu machine.

Download the wvdial + its dependencies from the following linkDownload.

Copy this package to your thumb drive from the machine which has an internet connection and connect it to the Ubuntu machine.

Assuming that you have copied the package from your thumb drive to the location /usr/local/src of Ubuntu machine. perform the following steps in exact order given below.

sudo su    (type in the admin password)

cd /usr/local/src/
tar -zxvf wvdial-ubuntu-wholepkg.tar.gz
cd wvdial-ubuntu-wholepkg

dpkg -i libxplc0.3.13_0.3.13-1build1_i386.deb
dpkg -i libwvstreams4.4-base_4.4.1-0.2ubuntu2_i386.deb
dpkg -i libwvstreams4.4-extras_4.4.1-0.2ubuntu2_i386.deb
dpkg -i libuniconf4.4_4.4.1-0.2ubuntu2_i386.deb
dpkg -i wvdial_1.60.1+nmu2_i386.deb

Success!  You can run "wvdial" to connect to the internet.
(You can also change your configuration by editing /etc/wvdial.conf)
Processing triggers for man-db ...

For BSNL EVDO users, edit the /etc/wvdial.conf file to add your username password and phone number(also uncomment the line by removing ; from the start of the directive). Also add the following line.

Stupid Mode = 1

to wvdial.conf file.

Use the command “wvdial” to connect to the internet. If the modem is not installed or not detected, you need to fix it first.

Please update me guys, if you need any further help.