to upload a file, the form encoding type must be set to multipart/form-data.
change:
<form action="tbFaqs_Insert.php" method="post" name="WADAInsertForm" id="WADAInsertForm">
to:
<form action="tbFaqs_Insert.php" method="post" enctype="multipart/form-data" name="WADAInsertForm" id="WADAInsertForm">