I use CPAN to install all my perl modules. It's not the only way to do it but it's a standard way for a lot of perl users.
To fire up CPAN go to the command line and enter:
perl -MCPAN -eshell
You'll then be asked to config. hitting return after each question is safe but you'll probably want to answer the bits about where you are so that you can pick servers near to you to get the perl files from.
CPAN does the installing of the modules for you just enter
install LWP
and off it'll go and install it for you.
If you're not logged in as root it may fail as it won't necessarily have permission to do the install part.
CPAN is particularly good because it will ask you if you want to install any modules that are missing that you need to install the module you're currently installing (dependencies) I seem to recall LWP does have some but they may already be there.
I'll keep an eye on the forum so post if you hit any problems. I run FreeBSD rather than Debian but I've used CPAN on FreeBSD, Redhat and OSX all happily most of the time. Sometimes a module won't install and if that happens you have to do it manually.
This may help if that happens:
http://search.cpan.org/~jhi/perl-5.8.0/pod/perlmodinstall.pod
It seems a lot of DA's features are PHP (webmail for example). I'm not sure going the DA route was the right one for me as I'm a mod_perl developer. So I shall be keeping an eye out for people suffering perl problems (at least while I'm still using DA)