i had this issue and the steps on blackberrys site helped me to resolve it:
from: BlackBerry Developer Site
In your existing Eclipse environment, follow the steps below:
From the Help menu, select Install New Software to open the Install window.
Click Add:
In the Add Site dialog, type the URL http://www.blackberry.com/developers/jar/win/java into the location text box and specify BlackBerry Java Plug-in Update Site in the name text box.
Click OK, BlackBerry Update Site appears in the Available Software list.
Select the BlackBerry Java Plug-in item and at least one BlackBerry SDK you want to work with. Choose the version of the BlackBerry SDK which ensures that your application is compatible with your intended target market. Read more about SDK versions.
Click Next.
Click Next after reviewing the items to be installed.
Check I accept the terms of the license agreement after reviewing the licenses.
Click Finish to begin installation.
After successfully downloading the files, you'll be prompted to restart Eclipse.