cant find file 'data_obs_1.dat'...

Carsten,

The very latest VisAD revision contains an error message in 
GoesCollaboration which tells users where to find these data
files if they aren't present at runtime.  You can find these
data files at: ftp://demedici.ssec.wisc.edu/pub/visad-2.0/paoloa-files.tar.Z

Let us know if this doesn't fix the problem.

Tom Rink