I had exactly the same problem and I solved it by uninstalling and
then reinstalling the Java 3d program. First go to the Satscape page
http://www.satscape.info/home/?q=node/2 , scroll down to the Satscape
download instructions and click on "Step 2 Download Java 3D Windows."
Save the j3d-1_5_2-windows-i586.exe file to your hard drive and then
double click on it. If you don't already have it installed, just go
through the installation process. If it is installed, you'll get a
screen with 2 choices (modify or uninstall). In my case, I selected
uninstall, and once that was done, I double clicked the exe file
again. This starts installation (starting with accept license terms)
and you just follow the prompts. After that, Satscape 2d and 3d worked
fine (I put a shortcut on my desktop linked to the Satscape.jar file
that you download from the Satscape site above).
Hope this works for you.
73,
Craig Kall, SM6JCD / WA4HNC
Tjörn Island, Sweden