man, i hav the same problem, except with a twist.
i made a copy of subsilver and called it subsilver-ftc (for fun), intending to just play with that style untill i got it right, but still hav the original 1 to fall back on.
well, i got that error straight away, and well, panicd.
i deled the style and all...
and wen that didnt fix it, i replaced the original subsilver with a fresh one from the zip file.
still didnt work.
is there a file somewhere that is saying ..find style file <oldstylename>...?
because if i could find that, i would just change it back to <newstylename>