You could probably just add it manually after the delete file like:
<?php
$WA_DeleteFileResult1 = false;
if(isset($_POST["DeleteButton"]) || isset($_POST["DeleteButton_x"])){
$WA_DeleteFileResult1 = WA_FileAssist_DeleteFile("../clientuploads/".($rsProject->getColumnVal("clientuploadID")) ."", "".($rsUploadedFiles->getColumnVal("clientfiles1")) ."");
@rmdir("../clientuploads/" . $rsProject->getColumnVal("clientuploadID"));
}
?>
That would remove the folder if it was empty after deleting the file and do nothing if there were still files in that folder.