There are two easier ways than using LWP::UserAgent if all you want to do is to download a file via HTTP:

• Use wget:

  system(qw( wget -O ), $target_name, $url) == 0
    or warn "Couldn't download '$url': $?/$!";
  [download]

• Use LWP::Simple (included in LWP):

  mirror( $url, $target_name );
  [download]