Seems there's lack of big-name talent available.
DREAM In Korea Cancelled! No Star Fighters, No Broadcast
Published: March 25, 2010
Korean MMA site MFight report that it was announced today that the April 24th DREAM Korea event, which Yoon Dong Sik, Jung Bukyung, etc. have been preparing for, has been cancelled. The reason for the cancel seems to be some star fighters not being available in April (Hong Man Choi and Denis Kang) which in turn led to the DREAM officials not being able to secure a deal for broadcast on Korean TV.
No word on any future date for an event in South Korea for DREAM or if it will even happen.
MFight report translated here.
Original Korean text here.