cannot insert data into database

[eluser]Unknown[/eluser]
I use CI 1.7.1 and ODBC database driver and i also have the same problem, my database config:

$db['factory']['hostname'] = "ConsultasSFT";
$db['factory']['username'] = "";
$db['factory']['password'] = "";
$db['factory']['database'] = "";
$db['factory']['dbdriver'] = "odbc";
$db['factory']['dbprefix'] = "";
$db['factory']['pconnect'] = TRUE;
$db['factory']['db_debug'] = TRUE;
$db['factory']['cache_on'] = FALSE;
$db['factory']['cachedir'] = "";
$db['factory']['char_set'] = "utf8";
$db['factory']['dbcollat'] = "utf8_general_ci";


sentences

$data = array(
'vre_timestamp' => "", //$vre_timestamp,
'vre_vld_id' => 1, //$vre_vld_id,
'vre_vms_id' => 2, //$vre_vms_id,
'vre_table_key' => 3, //$vre_table_key,
'vre_field_key' => 4, //$vre_field_key,
'vre_field_value' => 5 //$vre_field_value
);

$DB_default->insert('factory_validation_results', $data);

Line error

Fatal error: Call to undefined function: _remove_invisible_characters() in C:\Program Files\Apache Group\Apache2\htdocs\Pruebas PHP\developer\web\system\database\drivers\odbc\odbc_driver.php on line 248


any solution?

thanks