cvs question?

[Osmany Guirola Cruz]

Hi people

 I am learning in the use of cvs for sync my src and ports i use this 
command line and works perfectly

#cvs -d freebsdanoncvs at anoncvs.FreeBSD.org:/home/ncvs co src

but this line update my source tree with the current version 6.0 but i 
don't want this version then i do this

#cvs -d freebsdanoncvs at anoncvs.FreeBSD.org:/home/ncvs co -rRELENG_5 src

and get this error
cvs [checkout aborted]: cannot write /home/ncvs/CVSROOT/val-tags: 
Permission denied
 
What can i do? How can i obtain the src tree of 5-STABLE  and the ports 
tree via cvs "i can not use cvsup"?