Maybe debug with:
<?php
WA_DFP_SetupUploadStatusStruct("WA_UploadResult1") ;
if(isset($_POST["Insert_x"])){
WA_DFP_UploadFiles("WA_UploadResult1", "ProdImage", "3", "[ExistingFileName]_[Increment]", "true", $WA_UploadResult1_Params);
var_dump($WA_UploadResult1_Params);
die();
}