If you are running the BlackBerry JDE 7.0 with the BlackBerry Java Plug-in
v1.5, you need to launch the Mobile Data System (MDS) manually for the
BlackBerry simulator to run.
MDS is a framework that offers security, wireless connectivity, manageability
options, and development methods. You need it to run the simulator. It is a
known issue for BlackBerry that the simulator cannot launch MDS. This has
been fixed in BlackBerry JDE 7.1.