$_POST Problem with Admin Manage Submenu

I am designing a (simple) admin plugin to update a simple mySQL table.

I used the add_management_page('PDB Manage', 'PDB Manage', delete_others_pages, 'pdbmanage', 'pdb_manage_page')

I want to follow a simple structure:

<? if(!isset($pdbaction))
{
***list current table with a [link] to edit the entry***
}
?>
<?
if($_GET["pdbaction"]=="edit" || $_POST["pdbaction"]=="edit")
{
***call the edit form ****
}
?>
<? if ($_POST["$submit"])
   {
*** update the table ***
}
?>

The trouble I am having is it never recognizes the $_POST or $_GET arguments…

The [link] I am using when intially giving the table is <a href="edit.php?page=pdbmanage&pdbaction=edit&id=' . $id .'">[link]</a>

I have a suspicion that this is where I am failing…

Clear as mud? Any thoughts?