Here they are:
cvs -d:pserver:anonymous@netbpm.cvs.sourceforge.net:/cvsroot/netbpm login
cvs -z3 -d:pserver:anonymous@netbpm.cvs.sourceforge.net:/cvsroot/netbpm co -P modulename
"modualname" is not the modul that we will checkout.You must assign a name to replace it.I had made some mistakes here to neglect the commands of cvs is case sensitive.So you must replace it with "NetBpm" and it will work well.So the command like the below:
cvs -z3 -d:pserver:anonymous@netbpm.cvs.sourceforge.net:/cvsroot/netbpm co -P NetBpm
Good Luck!