Sorry to say.... I had this exact same problem twice in one month (when i was using my A1200 as my main machine). After that I moved to SFS and never looked back.
In my case I was able to salvage data by booting with no startup sequence, and copying as many files as I could to another HDD in the time I had before the GURU/reset. I had about less than a minute each time. Got my important stuff off it, trashed the rest.
You will need to reformat AFAIK. Sorry :/
- Paul
