1) To help troubleshoot, edit the following line:
$WA_redirectURL = "ticketbooth_Detail.php";
$WA_redirectURL = "";
to prevent the redirect, then add the following code just after the <body> tag to write the insert query to the screen:
<?php echo("SQL: ".$WA_Sql); ?>
post this back in your reply.
2) There is a know issue for this in the data assist download center page.
3) Yes, you could use remove the poster text field and replace it with a file filed of the same name, then use the File Manipulation -> Upload file behavior. see the data assist support page for a tutorial on adding digital file pro to data assist insert and update pages.