I discovered that the default resource in Korganizer was set to be an iCalendar file instead of a vCalendar file. But apparently, since it was already a vCal file, Korganizer couldn't handle that it was set to use it as an iCal file. When I changed it back to vCal, it was fine.
Well, it's good that it didn't break the file, but it should be able to figure out that it's trying to use the wrong format, and it should ask you to fix it, instead of saying, "Sorry, can't do what you want for some unknown reason."
pgpDoAiVcWuMb.pgp
Description: PGP signature