upload script fungerer ikke

jeg får denne her besked

Warning: move_uploaded_file(): SAFE MODE Restriction in effect. The script whose uid is 502 is not allowed to access / owned by uid 0 /home/virtual/xxxx.com/public_html/website/upload/thu.php on line 37


linie 37: move_uploaded_file($fra, $til);

hvor $fra og $til er defineret således:
$fra = $_FILES["upfil"]["tmp_name"];
$til = $konfiguration["upload_bibliotek"] . "/" . $_FILES["upfil"]["name"];

og sidst er $konfiguration["upload_bibliotek"]:

$konfiguration["upload_directory"] = "/home/virtual/xxxx.com/public_html/website/thumbnails";

jeg har chmod 777 på thumbnails directoriet

hvad kan problemet være??