Putting:

MASTER_SITE_SOURCEFORGE=http://twtelecom.dl.sourceforge.net/sourceforge/

into my /etc/mk.conf solved that problem. 

]       ON HUMILITY: to err is human. To moo, bovine.           |  firewalls  [
]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
] mcr@sandelman.ottawa.on.ca http://www.sandelman.ottawa.on.ca/ |device driver[
] panic("Just another Debian GNU/Linux using, kernel hacking, security guy"); [