The title makes a good, if dense, summary.

I have Asteroids currently "active" in Boinc Manager (BOINC v 8.2.11), but I have regular notices reporting "Invalid or missing account key" for Asteroids.

All the advice I've found on the Internet says to remove the project and re-add it.

I cannot, of course, remove the project, because it has four open tasks that are stuck in "Ready to Report", and I cannot make those go away.

How do I fix this? (It's taking up space on my disk, even if it's not much space, and it clutters up the Notices tab of BOINC Manager, and it's blocking me from getting more jobs from Asteroids.)

Bah, really, nobody knows? Nobody has any suggestions? Oh well, I'll just leave Asteroids there, incapable of getting new work, and cluttering my disk for nothing, I guess...