Hi swavek,
Strangely enough I had exactly the same problem as you and almost reached the stage of posting it here for help before I discovered the "read only" flag was set. I backed all my AH settings onto a CD when I got my new system. I think this was what set the flag (You can't modify files on a CD so it would make sense when you think about it) Did you perhaps do the same thing?
TTFN
snafu