CVS err "reading from server error -1 "

I tried to checkout the "DOM Conformance Test Suites" under the guide of "
http://www.w3.org/DOM/Test/Documents/DOMTSBuild.html"
But turned out to be a error as follow,anyone can tell me what's wrong?
thanks a lot.

C:\Documents and Settings\guanliyuan>set
> CVSROOT=:pserver:anonymous@dev.w3.org:/sources/public


> C:\Documents and Settings\guanliyuan>cvs logon

Logging in to :pserver:anonymous@dev.w3.org:2401:/sources/public

CVS Password:


> C:\Documents and Settings\guanliyuan>cvs logon

Logging in to :pserver:anonymous@dev.w3.org:2401:/sources/public

CVS Password:


> C:\Documents and Settings\guanliyuan>cvs checkout 2001/DOM-Test-Suite

cvs checkout: Updating 2001/DOM-Test-Suite

U 2001/DOM-Test-Suite/.cvsignore

U 2001/DOM-Test-Suite/README.cvs

cvs [checkout aborted]: reading from server: error -1