How to grant read-only access

[highegg]

Hello,
I am a newbie to CVS and can't figure out how to solve my problem:
I have my own CVS repository on our company server (/home/hajek/cvs).
 I would like to provide a read-only access to it to
other users (that are not members of me or my group). However, if they
want to download a project with

cvs -d sun1.vzlu.local:/home/hajek/cvs checkout parsec

cvs fails because it requires write-access to the directories to create
locks.
I also created the "readers" and "writers" files in the CVSROOT
repository
(/home/hajek/cvs/CVSROOT)
but it still doesn't work. Is there any way to get this right?
Many thanks in advance,
Jaroslav