Active Record Class Updateing

[eluser]The Casual Bot[/eluser]
I'm not to sure about this but i have searched the forum and the userguide for a answer but no luck yet!

I'm trying to up data a MSSQL database using the ODBC driver but i cant set a NULL value it returns the following error

Fatal error: Call to undefined method CI_Input::_remove_invisible_characters() in C:\wamp\www\mednetuk\system\database\drivers\odbc\odbc_driver.php on line 279

any ideas