Well, not quite. I'm running windows ME, I'm not some kind of AVR newb (I've been using STK for 2 years), and it's an official "upgrade" included within AVR Studio v4.11.401 itself. The board is an official STK500, which I desparately need because it can program, verify, read, fuse & lock-bit virtually any AVR device (plus some of their 8051 devices). It also cost $90 and I prefer to restore it rather than buy one anew.
The part that frustraits me is AVR Studio claimed I would have errors only if I didn't upgrade. On top of that, there's no indication of what caused the Flash error, and the IDE never offered the original firmware back once the problem appeared. My best bet might be to find the original firmware file, but mostly everybody got rid of theirs when they upgraded to v4.11 like I did. :x