Steve Dunn , Jun 07, 2010; 08:22 p.m.
What she's done is what the manual suggests, and the only thing left in what the manual suggests is what you said at the end. And the manual's description of error 30 gives no clue at all as to what sort of problem it may be, which makes it hard to suggest other possible causes.
I suppose if you want to try a bunch of other things before sending it in, there are some old standby suggestions that sometimes cure other errors: clean all contacts (battery, battery compartment, lens, lens mount, plus flash and flash mount if a flash might be involved), try a different lens, try a different CF card, try reformatting the flash card in the body. My guess is most or all of them won't fix it, but they're all quick and (assuming she or someone she knows has another lens and a second CF card) free, so it may be worth a shot.
Oh - when you say "battery", did you mean "batteries"? Both the main battery and the lithium button cell need to be removed for a proper reset.