Here are a few things to try (no guarantee they will help):

 use strict;  # Always a good idea

 my $mesg = $ldap -> search(filter => "(cn=Domain Users)",   # Take ou
+t the & , since the filter has only ONE entity
                         base => "dc=domain,dc=local",
                         sizelimit=> 9999,                # Try adding
+ this
                         scope => "subtree" );            # Try adding
+ this
 die $mesg->error if $mesg->code; # Always error-check
 foreach my $entry ($mesg->entries) {
    $entry->dump;
 }
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Update: ALso try to search for ONLY Groups:

   filter => "(&(objectCategory=group)(cn=Domain Users))",
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I did not see an "entry" method in the object returned by LDAP search. Try "entries" as in my code above.