It depends on your version of Cognos. As of 10.1 initial release, there was no support for Active Reports on mobile devices, so that link is correct for that version.
As of 10.1 Refresh Release 1 (AKA 10.1.1) it is supported on the iPad using the Cognos Mobile application. You can see the Active Reports section was added to the Supported Environments page for 10.1.1: http://www.ibm.com/support/docview.wss?uid=swg27022474