emacs not saving files

[michael bane <cs@networkingnewsletter.org.uk>]

I've a file $HOME/.rsync-EXCLUDE (listing files to exclude from my  
rsync based backup scripts) but when I try and save it, emacs refuses  
with message
	File /Users/mkbane/RCS/.rsync-EXCLUDE is not an RCS master file

ANy thoughts? (I need to check this holds for all my emacs... this  
particular instance was on a different Linux dist since my Debian box  
is offline this mortning)

many thanks
m