Invalid lockserver version

Lock server is used in client-fileshare mode when client executable
directly touches CVS repository. This is not recomended, instead you have
to use client-server access method. It seems that you have cvs-nt up and
running so you can use it in client server mode even on local pc (using
localhost as server address). The protocol selection (:pserver:, :sspi: and
so on) depends on your preferrence, but initially you can go with :sspi:
which will use windows domain authetication.
As for incompatiblity with lock server version this seems because of you
use both client and server on same workstation in client-fileshare mode. If
you still willing to use system in such mode (which is not recommended)
then you have to ensure that all applications use the same CVS client
version. Our plug-in can use almost any client available you just have to
point path to it in "CVS executables" page of options window.