Looks like the actual source code is at:
Some comments from sf.net page:
# Thumbs down
It is SOOO outdated, and even their own sales people have admitted
that they are no longer supporting the community version, which is in
total violation of the GPL license under which it was originally
created. Don't lose hope though! There is a newer and much better
version of an opensource web-meeting system called "Big Blue Button"
at www.bigbluebutton.org. We are working with them to help us migrate
away from Dimdim to their much faster and smoother platform. The video
quality is 100% better than Dimdim, and their support staff is
fantastic! Screw Dimdim, and let them hang themselves with their
abandonment of the community that got them to where they are now.
GoToMeeting, WebEx, BBB and Cisco will kill them off anyway! Don't let
the crooks at Dimdim get you down! Just leave them behind and help
drive the revolution with the "Big Blue Button"!
- From: Mathieu Malaterre <email@example.com>