First of all I'd like to thank everybody for the "pronto" help.
But the problem is that
1. My shell doesn't have an enviroment variable called CLASSPATH;
2. I, then, tried to edit my .profile file, by adding the variable to it,
i.e.
CLASSPATH=/usr/java/jdk1.3.1_01/lib/jdbc7.1-1.2.jar
export PATH CLASSPATH
but, still doesn't work.
3. When I run the application in the Forte 3 enviroment, it works
perfectly, but that becuase the IDE requires to copy the driver to the
IDE's directory.
4. I use the same enviroment for developing and running the application.
Thanks again.