You shouldn't stringify your "logic" elements. It will work better if you store the actual references to the sub and its arguments:

   push @incl, [ \&CreateLoginForm, \$page, \$error ];

   # later on:

   foreach my $incl ( @incl ) {
       my ($sub, @args) = @$incl;
       $page .= $sub->(@args);
  }
[download]

Depending on the logic of the rest of your code, you may be better off storing the actual arguments instead of references to them:

  push @incl, [ \&CreateLoginForm, $page, $error ];
[download]

But I can't determine that from what you've told us. It might avoid surprises though.

Question: is the $page you push into @incl the same as the $page you use in the foreach loop?