Interesting. I've been working on an Excel application for months and
all the sudden started getting this error today for no reason.
Coincidentally I was listening to Bloomberg radio all day via Windows
Media Player, which I normally don't do. Seems like there must be
some kind of problem with Bloomberg, but I don't see how it could
affect XL. The code interruption seemed random and it even entered
break-mode when there was no break! Very strange.

As soon as I rebooted the problem disappeared. FYI, this was on NT
and XL97.