Your first row should have a null value in the second element:
$tmp1 = array(Mike, null, );
$tmp2 = array(Jim, Mike, test1);
$tmp3 = array(Bob, Jim, Bob Sponge);
$tmp4 = array(Carol, Bob, );
as no element can be its own parent (Mike cannot be have Mike as a
parent) and there must be a root
I fixed some quoting issues in getData.php, but still the same problem:
?php
$return_array = array();
$tmp1 = array(0 = Mike, 1= Mike, 2 =);
$tmp2 = array(0 = Jim, 1= Mike, 2 =test1);
$tmp3 = array(0 = Bob, 1= Jim, 2 =Bob Sponge);
$tmp4 = array(0 = Carol, 1= Bob, 2 =);
array_push($array, $tmp1);
