just got rid of the
IDE (Eclipse), gave it an extra 80m for overhead
and it works on my machine
$
java -Xms1104m -Xmx1104m Scenarios
$ java -version
java version "1.6.0_17"
Java(TM) SE Runtime Environment (build 1.6.0_17-b04)
Java HotSpot(TM) 64-Bit Server VM (build 14.3-b01, mixed mode)
M