Thanks for the link. I actually had been to the page that the above link directs to, but I neglected to do BOTH parts of the deinstall procedure (I think it's odd that it would be a two-step process, but then again, I'm not much of a hardcore programming type).

And again, it wasn't clear that I even needed to DO an uninstall, since the N900 was showing the default kernel running.

But anyway, I did finally uninstall successfully, and then reinstalled the power kernel, so I'm back to OC status. Thanks for the help.