Hello,

I can reproduce the error - but not in line 124. The problem is the $search_string_array, which exists iff the search box is not blank. To fix this bug, just initializes the variable by an empty array at line 52

$search_string_array = array(); // new line of code
foreach ($search_array as $item) {
 if (my_strpos($item, ' ', 0, CHARSET)) {
  $item = '"' . $item . '"';
 }
 $search_string_array[] = $item;
}
$search = implode(' ', $search_string_array);

I add this change to github, too.

/Micha