Solution:
To prevent DataHub Console from closing unexpectedly, add the following code into <DataHub folder>\datahubconsole\datahubconsole.ini
-vmargs
-Dorg.eclipse.swt.browser.DefaultType=mozilla
When a synchronized entity is given a new stereotype, it will be treated as a new entity in DataHub and the eventual associations previously tied to it are lost. No Magic Inc. is working on a Service Pack for DataHub 3.0 that will address and solve this limitation. Per current plans, the Service Pack will be released in mid-May 2009. Until the Service Pack is available, users can avoid the occurrence of this issue by not changing the stereotypes of entities after these have been imported in DataHub and associations created. Please note that the auto-numbering feature of SysML 16.5 plugin for MagicDraw adds new stereotypes to the SysML entities. Therefore these entities, if already imported in DataHub, will be treated as new ones after re-numbering.