whenever i click the update manager i get the following errors ?

A unresolvable problem occurred while initializing the package information.

Please report this bug against the 'update-manager' package and include the following error message:

'Wuplicate sources.list entry http://archive.ubuntu.com hardy/universe Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_hardy_universe_binary-i386_Packages), Wuplicate sources.list entry http://archive.ubuntu.com hardy/multiverse Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_hardy_multiverse_binary-i386_Packages), E:Problem parsing dependency Depends, E:Error occurred while processing btnx (NewVersion1), E:Problem with MergeList /var/lib/apt/lists/repoubuntusoftware.info_dists_harty_all_binary-i386_Packages, E:The package lists or status file could not be parsed or opened.'


what should i do to solve this problem ?

Which ubuntu release do you have?

Try

sudo apt-get clean
sudo apt-get update
sudo apt-get -f upgrade

report the output

However - have you manually added any repositories? Check the spelling... vis:
(my emphasis).

I corrected the spelling but still i am getting the message

W: Duplicate sources.list entry http://archive.ubuntu.com hardy/universe Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_hardy_universe_binary-i386_Packages)
W: Duplicate sources.list entry http://archive.ubuntu.com hardy/multiverse Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_hardy_multiverse_binary-i386_Packages)

I am using ubuntu 8.04.1

BTW updates are happening

Well, that's half your errors taken care of. The dep errors were clearly a result of the spelling error.

This error is saying you have multiple entries in /etc/apt/sources.list - edit that file to remove the duplicates. It looks like the universe and multiverse lines have been duplicated... maybe you added them by hand without realising they were already there?

i tried what you said now i am getting this error

user@ubuntu:~$ sudo apt-get install mplayer
[sudo] password for user:
Reading package lists... Error!
E: Problem parsing dependency Depends
E: Error occurred while processing btnx (NewVersion1)
E: Problem with MergeList /var/lib/apt/lists/repoubuntusoftware.info_dists_hardy_all_binary-i386_Packages
E: The package lists or status file could not be parsed or opened.
user@ubuntu:~$

BTW this is my /etc/apt/sources.list file

#
# deb cdrom:[Ubuntu 8.04.1 _Hardy Heron_ - Release i386 (20080701)]/ hardy main restricted

# deb cdrom:[Ubuntu 8.04.1 _Hardy Heron_ - Release i386 (20080701)]/ hardy main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.

deb http://archive.ubuntu.com/ubuntu/ hardy main restricted
deb-src http://archive.ubuntu.com/ubuntu/ hardy main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.

deb http://archive.ubuntu.com/ubuntu/ hardy-updates universe
deb-src http://archive.ubuntu.com/ubuntu/ hardy-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu/ hardy multiverse
deb-src http://archive.ubuntu.com/ubuntu/ hardy multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu/ hardy-updates multiverse

## Uncomment the following two lines to add software from the 'backports'
## repository.
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://in.archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse
# deb-src http://in.archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository. This software is not part of Ubuntu, but is
## offered by Canonical and the respective vendors as a service to Ubuntu
## users.
deb http://archive.canonical.com/ubuntu hardy partner
deb-src http://archive.canonical.com/ubuntu hardy partner

# Line commented out by installer because it failed to verify:
# deb http://security.ubuntu.com/ubuntu hardy-security main restricted
# Line commented out by installer because it failed to verify:
# deb-src http://security.ubuntu.com/ubuntu hardy-security main restricted
# Line commented out by installer because it failed to verify:
# deb http://security.ubuntu.com/ubuntu hardy-security universe
# Line commented out by installer because it failed to verify:
# deb-src http://security.ubuntu.com/ubuntu hardy-security universe
# Line commented out by installer because it failed to verify:
# deb http://security.ubuntu.com/ubuntu hardy-security multiverse
# Line commented out by installer because it failed to verify:
# deb-src http://security.ubuntu.com/ubuntu hardy-security multiverse

#ULTAMATIX REPOS START

deb http://repoubuntusoftware.info hardy all
deb-src http://security.ubuntu.com/ubuntu hardy-security multiverse
deb http://security.ubuntu.com/ubuntu hardy-security multiverse
deb-src http://security.ubuntu.com/ubuntu hardy-security universe
deb http://security.ubuntu.com/ubuntu hardy-security universe
deb-src http://security.ubuntu.com/ubuntu hardy-security main restricted
deb http://security.ubuntu.com/ubuntu hardy-security main restricted
#ULTAMATIX REPOS END

deb http://archive.ubuntu.com/ubuntu hardy universe
deb-src http://archive.ubuntu.com/ubuntu hardy universe multiverse

- what did you try? I said many things - be specific. Did you find some duplicate entries in the sources.list and remove them?

Looking at the ultimax repos
Should be
deb http://repoubuntusoftware.info harty all

... after all - this is the address of the Ubuntu Ultimate Edition, which was code-named "Harty Hotrod" <sigh>.
Are you perhaps running the ultimate edition? Did you "correct" the spelling for any others too? Please note, I only said to "check" the spelling - you were supposed to make sure it was incorrect before changing.

So - it looks like the original dep errors vanished because you were no longer accessing the harty repo. Put it back and you should be right where you started - with only the first half of the errors.

Which takes us back to the original advice: (I've added a line)

sudo apt-get clean
sudo apt-get check
sudo apt-get update
sudo apt-get -f upgrade

The rest are the security repos...