The beyondcvs project's CVS data is in read-only mode, so the project may have switched over to another source-code-management system. To check, visit the Project Summary Page for beyondcvs and see if the menubar lists a newer code repository, such as SVN or Git.
The CVS data can be accessed as follows.
You can run a per-module CVS checkout via pserver protocol:
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.all.feature
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.feature
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.perforce
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.perforce.feature
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.releng
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.svn.subclipse
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.svn.subclipse.feature
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.svn.subversive
cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/beyondcvs co -P org.eclipse.externaltools.svn.subversive.feature
You can view a list of files or copy all the CVS repository data via rsync (the 1st command lists the files, the 2nd copies):
rsync -a a.cvs.sourceforge.net::cvsroot/beyondcvs/
rsync -ai a.cvs.sourceforge.net::cvsroot/beyondcvs/ /my/local/dest/dir/
If you are a project admin for beyondcvs, you can request that this page redirect to another repo on your project by submitting a support request.