Something

<?
$data = preg_split("/\\\/", $row["filepath"]);

if (count($data) == 1) {
	$struct[$data[0]] = $row["fileID"];
}
elseif (count($data) == 2) {
	$struct[$data[0]][$data[1]] = $row["fileID"];
}
elseif (count($data) == 3) {
	$struct[$data[0]][$data[1]][$data[2]] = $row["fileID"];
}
elseif (count($data) == 4) {
	$struct[$data[0]][$data[1]][$data[2]][$data[3]] = $row["fileID"];
}
elseif (count($data) == 5) {
	$struct[$data[0]][$data[1]][$data[2]][$data[3]][$data[4]] = $row["fileID"];
}
elseif (count($data) == 6) {
	$struct[$data[0]][$data[1]][$data[2]][$data[3]][$data[4]][$data[5]] = $row["fileID"];
}
elseif (count($data) == 7) {
	$struct[$data[0]][$data[1]][$data[2]][$data[3]][$data[4]][$data[5]][$data[6]] = $row["fileID"];
}
elseif (count($data) == 8) {
	$struct[$data[0]][$data[1]][$data[2]][$data[3]][$data[4]][$data[5]][$data[6]][$data[7]] = $row["fileID"];
}
elseif (count($data) == 9) {
	$struct[$data[0]][$data[1]][$data[2]][$data[3]][$data[4]][$data[5]][$data[6]][$data[7]][$data[8]] = $row["fileID"];
}

?>