package installation problem

[pinkul goyal]

hi,
i was trying to intall real player by following the ubuntu guide.it
was written in that i have to add the PLF repositories.after that i
have to reload the package information but i am unable to do that.it
gives an error mesg

Could not download all repository indexes

The repository might be no longer available or could not be contacted
because of network problems. If available an older version of the
failed index will be used. Otherwise the repository will be ignored.
Check your network connection and the correct writing of the
repository address in the preferences.


The following problems were found on your system:

E: Malformed line 34 in source list /etc/apt/sources.list (dist)
E: Unable to lock the list directory

then i went to add or remove programs.there the error mesg was

Failed to check for installed and available applications

This is a major failure of your software management system. Check the
file permissions and correctness of the file '/etc/apt/sources.list'
and reload the software information: 'sudo apt-get update'.

if i am running the terminal then also the same error comes

pinkul at pinkul-desktop:~$ sudo apt-get install rar unrar
Password:
E: Malformed line 34 in source list /etc/apt/sources.list (dist)
E: The list of sources could not be read.
pinkul at pinkul-desktop:~$


plz help me