Try this:

setenv CVS_RSH ssh
setenv CVSROOT anoncvs@anoncvs.netbsd.org:/cvsroot
cd /usr
cvs checkout -rnetbsd-1-5 -PA src

Or you could use another CVSROOT of course.

Or when you insist to use pserver:

setenv CVSROOT :pserver:anoncvs@anoncvs.netbsd.org:/cvsroot
cvs login
(anoncvs password)
and then cvs checkout bla bla

In the latter case you shouldnt use CVS_RSH of couse.
Bye,

Mipam.