I may be missing something, but the only thing that looks questionable to me is the quotes and maybe the parenthesis, I would edit your /etc/lilo.conf file (after backing it up) and change:

default="Windows(hda1)"
and
label="Windows(hda1)"

to:
default=Windows
and
label=Windows

and see if that gets rid of the error.
Note: in linux if an error doesn't cause problems it may be best to ignore it!

HTH

~rock