Hey there,
In this build we added .bik videos that play at the start and end of levels (the squares appearing animation for example) but since then we've had report that these crash Dream sometimes. it sounds like it may be doing the same for you.
A quick way to try and fix it is to go to Dream\UDKGame\Movies... and delete the following
Actone.bik
IntoBlack.bik
IntoWhite.bik
Intro.bik
after that try using the launcher to delete your save data folder and start the game again. Let us know if it works or still crashes and I'll do some more digging