This is where using Dynamic values gets tricky.
the folder name should end with a slash. so the more correct code change would be adding the slash to the folder setting rather than the file name setting:
("../apps/".$row_deleterecord['lname'] ."/", "".$row_deleterecord['cert'] ."")
if you select a static folder name, it _will_ automatically add the slash to the end, but with a dynamic value, there's no way for the GUI to know that the slash is not already a part of the value.
so if we where to automatically add a slash for dynamic folders and the value of your recordset already contained the slash:
$row_deleterecord['lname'] = "a_folder/"
then that would would have broken the delete also as the folder name would now contain 2 slashes: