Rule number 1 when working with forms:
All form Processing must occur on the forms action page
if the form is on "ck-listing.php" and the action is set to another page, in this case "ck-confirm.php":
<form action="ck-confirm.php" method="post" enctype="multipart/form-data" name="form1" id="form1">
the processing must occur on the ck-confirm.php page.
by changing the post to point to itself, you have set the form to post to the page that has the upload behavior on it, which is why the upload is successful.
if the action points to the ck-confirm.php page, the upload behavior must be on the ck-confirm.php page