1.8RC4 Upgrade - Error - SetFetchMode() on a non-object

[Kennedy]

Apache 2.
I'm receiving a Fatal error message with the Database upgrade 1.7.4 -> 1.8(RC4) Fatal error: Call to a member function SetFetchMode() on a non-object in ..../lib/functions/database.class.php on line 101... another error preceeded it: ADONewConnection: Unable to load database driver'
Here's the code from the php file.
function database($db_type)
{
// 20080719 - franciscom
$fetch_mode=ADODB_FETCH_ASSOC;
$this->db = NewADOConnection($db_type);

// added to reduce memory usage (before this setting we used ADODB_FETCH_BOTH)
if($db_type == 'mssql')
{
$fetch_mode=ADODB_FETCH_BOTH;
}
This is line 101 $this->db->SetFetchMode($fetch_mode);
}

Questions:
What Database driver is it failing to load, and adobe one?
Is db_type == 'mssql' supposed to be db_type == 'mysql'?
Can anyone help me resolve or bypass this error safely?

[havlatm]

Check your web installation if all required modules are loaded. Maybe the next page helps: http://php.mirror.camelnetwork.com/manu ... lation.php