Thanks for the replay.
Yes i can able to download module using "wget".
I have installed "perl-libwww-perl" and the error says

cpan> install CPAN::Mirrors
Fetching with LWP:
  ftp://mirrors.sohu.com/CPAN/authors/01mailrc.txt.gz
CPAN::LWP::UserAgent->new dies with Can't locate HTTP/Config.pm in @IN
+C (@INC contains: /usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-mu
+lti /usr/lib/perl5/site_perl/5.8.8 /usr/lib/perl5/site_perl /usr/lib/
+perl5/vendor_perl/5.8.8/i386-linux-thread-multi /usr/lib/perl5/vendor
+_perl/5.8.8 /usr/lib/perl5/vendor_perl /usr/lib/perl5/5.8.8/i386-linu
+x-thread-multi /usr/lib/perl5/5.8.8) at /usr/lib/perl5/site_perl/5.8.
+8/LWP/UserAgent.pm line 770, <FIN> line 2.

Can't call method "mirror" on an undefined value at /usr/lib/perl5/5.8
+.8/CPAN.pm line 2506, <FIN> line 2.
[download]

Update : Thanks for ur help i have manually installed the "HTTP::Config" module now its working fine.
Once again thanks