We double checked, and the last DMG beta is ok on our Mac computers.
As usually, there is a quiet long security delay (1 to 2 minutes with our computers) to see the window at first start (
viewtopic.php?f=10&t=603).
May be this is another problem (?)
In order to know this new problem is only with your computer or not, please try on another Mac computer, and tell us if still problem or not.