How to expunge sick revision?

[kynn]

I used "cvs remove" to get rid of some unwanted files, and CVS
informed me to use "commit" to make the removals final.  OK, so I did
"cvs commit", and CVS proceeded to commit everything in sight, not
just the removals as it had announced.  Among the files it committed
was a source file in a completely sick and dangerous state (it
contains a potentially devastating bug).  So now this completely sick
file is indelibly enshrined in the repository.  It is simply obscene
to have such potentially dangerous code stored in the repository, but
as far as I've been able to find there is nothing I can do about it.
OK, fine.  Life is too short, etc., and I try to get on with mine by
reverting to an earlier (non-buggy) revision of the rotten file; I
pull it out with "cvs update -r x.x".  I make some changes, but when I
try to commit them, I get:

  cvs commit: sticky tag `x.x' for file `BloodyMurder.c' is not a branch

So the completely rotten version x.(x+1) that should have never been
stored in the repository in the first place is now blocking my
attempts to commit a correct revision.  How can I fix this horrible
mess?

Thanks,

Kynn

PS: Please, Cc me in your replies.