can Not run visad correctly

Hi,

I am new to visad. After compiling visad (with jdk1.2beta4 and java3d), it
seems that I can not get correct result when running it. For example,
after I typed "java GeoDisplay" or "java Simple", I always got nothing but
some black-white lines in the widget generated. I met similar problem when
using spreadsheet and loading files like b2rlc.nc, rad.nc or sphere.jpg. 

what's wrong with this? 

Thanks a lot.

Lewis