Charlotte, based from what I've read online, you're correct. One thing I'm going to try when I go home at lunchtime is running the in-sink-er-a-tor and then trying the dishwasher again; mine is hooked up to drain through that (though technically it's not supposed to be). But I suspect it's time for a new dishwasher. Lowe's online shows a comparable model to the one I have for about $300, though I'm expecting there may be some kind of "code uppage" that has to be done like with my hot water heater.

I'm going to try to do it as soon as possible to try and get it in before I leave again. (Though it won't be a big deal if I can't; I'll just buy a dish-drainer and use that until I can get the thing installed.)