It looks like you did it manually and have some issues...
$WA_AB_Split . "".($WA_DFP_UploadStatus["WA_UploadResult2"]["serverFileName"]) ."" . $WA_AB_Split . "".($WA_DFP_UploadStatus["WA_UploadResult2"]["serverFileName"]) ."" . $WA_AB_Split . "".($WA_DFP_UploadStatus["WA_UploadResult1"]["serverFileName"]) ."" .($WA_DFP_UploadStatus["WA_UploadResult3"]["serverFileName"]) ."". $WA_AB_Split
should be:
$WA_AB_Split . "".($WA_DFP_UploadStatus["WA_UploadResult1"]["serverFileName"]) ."" . $WA_AB_Split . "".($WA_DFP_UploadStatus["WA_UploadResult2"]["serverFileName"]) ."" . $WA_AB_Split . "".($WA_DFP_UploadStatus["WA_UploadResult3"]["serverFileName"]) ."". $WA_AB_Split