My ex-Sub card seems to have stopped updating using OSCAM too :(
Putting it in a Sky+ HD box and Pressing Services 0 0 1 and selecting the New Install option (with it connected to Broadband) instantly got it reactivated until late April :)
* Could be a coincidence with Motors TV now on Freeview and me finishing off Spooks I'm much less frequently using the card by watching Sony TV, Sony Movies, and STV Glasgow very occasionally so it's possible I'm missing the updates more frequently.