mysql - Having An Issue Backing Up MY Database From Php

the issue that I'm having is with the fopen(), fwrite(), and fclose() function. This is the error I am receiving:

Warning: fopen(/db-backup-salisbury_school-20121128-021138.sql) [function.fopen]: failed to open stream: Permission denied in C:\inetpub\wwwroot\omarejaz\sbyschool\q5.php on line 177

Warning: fwrite() expects parameter 1 to be resource, boolean given in C:\inetpub\wwwroot\omarejaz\sbyschool\q5.php on line 178

Warning: fclose() expects parameter 1 to be resource, boolean given in C:\inetpub\wwwroot\omarejaz\sbyschool\q5.php on line 179

The code for this portion of php can be found below any help would be greatly appreciated!

 * Save SQL to file
 * @param string $sql
 */
protected function saveFile(&$sql, $outputDir = '.')
{
    if (!$sql) return false;

    try

    {
        $handle = fopen($outputDir.'/db-backup-'.$this->dbName.'-'.date("Ymd-His", time()).'.sql','w+');
        fwrite($handle, $sql);
        fclose($handle);
    }
    catch (Exception $e)
    {
        var_dump($e->getMessage());
        return false;
    }


    return true;
}

}
?>