There are several problems here. One of them is that your Gnu Java ("gjc") compiler doesn't appear to be configured correctly.
A more fundamental problem, however, is that Gjc happens to be the default (instead of the very different - and, IMHO, better) Sun Java compiler.
I would strongly encourage you to:
a) download the Sun JDK from Sun's web page
b) *de-install* Gjc (to avoid potential conflicts between Sun Java and GJC)
c) Install Sun Java (and only Sun Java - at least until your development environment is stable)
You can download the Sun JDK here:
Sun's web site has extensive documentation for installing and using Java under Linux (it's really quite straightforward).
'Hope that helps .. PSM