emacs vc/rcs problem

[Jaroslav Hron]

Anybody experienced recently a problem with the version control in 
emacs??


Registering (C-x v i) or checking in (C-x v v) any file with vc
(rcs as a back end) fails with message 



vc-back end-admin: Symbol's value as variable is 
         void:vc-default-back-end 

for the registering and for the check in it says 

setq: Symbol's function definition is void: vc-locking-user 




      Any suggestions why it is not working?
JH