Fix minor autoloading issue

OpenSQLManager.php

@@ -121,6 +121,12 @@ if ( ! function_exists('do_include'))
  */
 function osm_autoload($class)
 {
+	// Use the ibase_ functions instead of PDO::Firebird
+	if (strtolower($class) === 'firebird')
+	{
+		return;
+	}
+
 	$class = strtolower($class);
 	$widget_path = BASE_DIR . "/widgets/{$class}.php";
 	$window_path = BASE_DIR . "/windows/{$class}.php";