help with vc-rcs: does not recognize vc status of file

[evan]

Dear emacs users,

I have emacs 23 with the following configuration in my .emacs:
(setq vc-rcs-checkin-switches "-l")

It seems to me that emacs doesn't recognize the -l switch when
checking in a file (i.e. that the file is already checked out and
locked by me). When I execute C-x v v, in the minibuffer  it says

Running co -l -r1.21 RCS/file.txt,v...FAILED (status 1)

and pops-up a buffer saying

RCS/file.txt,v  -->  file.txt
revision 1.21 (locked)
co: writable eye.f90 exists; checkout aborted

This works fine with emacs 22. I just checked that.

If I remove the -l switch, then C-x v v checks in the file and then I
have to do a C-x v v again to check it out.

Has anyone else experienced this behavior? Is there a way to fix this?