use WWW::Mechanize;
use WWW::Mechanize::TreeBuilder;

my $mech = ...

my @list = $mech->look_down(_tag => "a", class => "links");
foreach (@list) {

  # see if I want to skip this row, or save/print some
  # data and follow link to next page

  # printing data works fine

  # following a link breaks the loop

  $mech->get($new_url); # finds the page no problem
  
  # do stuff on page, then go back

  $mech->back();

  # complaint is of unitialized "tag", from the look_down
  # call I assume?
}