I've encountered this issue on a Dell Vostro 360 all in one. I've tried installing the latest driver from Nvidia. I've tried Ironhide (although I may have done it incorrectly) and as of this post I am unable to install bumblebee from the PPA (were they removed?).
I was denied permission (even though I accepted the key) to the acpi_call script, and am now currently at at loss.
Is there anyone who has established a solution to this?
I'm running Ubuntu 11.10.