problem with NWDS perspective

hi all,

i am not able to open the "Data modeller" for a component and

"Navigation modeller" for a window in a component for any project in NWDS in webDynPro perspective.

when i open the context menu for a component and click on "open data modeller" ....it doesnt open the data modeller i.e the diagram view

how can i open the data modeller and navigation modeller.

help me ....

regards,

Sudheer.