Is there an issue with the dbutil class in 1.7?

[eluser]Joe_Archer[/eluser]

Code:

function export(){
    $result = $this->subscribers->getsubscriberlist();
    $filename = "subscribers";
    header("Content-type: application/x-msdownload");
    header("Content-Disposition: attachment; filename=$filename.xls");
    echo($this->dbutil->csv_from_result($result));
}

returns
An Error Was Encountered

You must submit a valid result object

but I know the result object is valid as I'm using the same resultset returned by getsubscriberlist(); elsewhere in the app without problems.

Code:

print_r($result);

returns:
ci_db_mysql_result Object ( [conn_id] => Resource id #35 [result_id] => Resource id #47 [result_array] => Array ( ) [result_object] => Array ( ) [current_row] => 0 [num_rows] => 2 [row_data] => )

I get the exact same results with

Code:

$this->dbutil->xml_from_result($result);

I'm using the exact same boilerplate code in a 1.6 app without any problems...