[Xenon]

you can install it, the chance of this bug occurs is nearly 0

if you want to be absolutley sure use instead of this:

PHP Code:

    if (!$allowduplicates) {
      if ($result=$DB_site->query_first("SELECT attachmentid
                                         FROM attachment
                                         WHERE hash = '".addslashes($attachmenthash)."'")) {
        $attachmentid = $result[attachmentid];
      } 


this:

PHP Code:

    if (!$allowduplicates) {
      if ($result=$DB_site->query_first("SELECT attachmentid,filedata
                                         FROM attachment
                                         WHERE hash = '".addslashes($attachmenthash)."'")) {
       if($filestuff==$result[filedata]) {
        $attachmentid = $result[attachmentid];
      } 


and add a } directly before return $attachmentid;