Permalinks generate 404 errors in admin only.

I have a problem. When I define a custom permalink format, be it one that WordPress supplies or one I’ve concocted myself, within a few minutes I will start getting 404 errors in my admin, but the front pages use the new permalinks just fine.

Poking at it, I have learned this much, which may or may not be related:

1. The front pages seem to start using the new permalinks at about the same time the backend starts 404ing. This could be linked to the the supercaching.
2. Renaming the .htaccess makes the problem go away.
3. Re-engaging the htaccess, the problem starts up again in a few minutes unless I switch to the “default” permalink convention.

I’m not sure what is going on. Any clues?

Lastly, I apologize that this post was posted multiple times in the plugins forum. It was an accident, and if I were able to delete them, would. Gosh knows, I’d like to!