List_Exercises.php?page=2 gives error in admin area

Hi.I have added a custom menu item through Admin Menu Editor plugin.And I want to paginate the results coming from the database in this page.Problem is, though http://yoursite/wp-admin/List_Exercises.php works fine, when I try to go to 2nd page http://yoursite/wp-admin/List_Exercises.php?page=2 I get following error:
You do not have sufficient permissions to access this page.

I have added the file in page as follows:

$targetpage = "List_Exercises.php";

I can provide part of my code if needed.Please help in this regard.:confused:

Found solution today!!Problem was with ?page=2.Just changed variable to paged=2 and it started working.Might help someone else :slight_smile: