The example above isnt right. Replace with this:
<?php
$mbox = imap_open("{your.imap.host}", "kalowsky", "password", OP_HALFOPEN)
or die("can't connect: " . imap_last_error());
$quota = imap_get_quotaroot($mbox, "INBOX");
if (is_array($quota)) {
$storage = $quota['STORAGE'];
echo "STORAGE usage level is: " . $storage['usage'];
echo "STORAGE limit level is: " . $storage['limit'];
$message = $quota['MESSAGE'];
echo "MESSAGE usage level is: " . $message['usage'];
echo "MESSAGE usage level is: " . $message['limit'];
}
imap_close($mbox);
?>