Dear Francesco,
thanks for Your help.
I have sun-java 6 installed.
I've unzipped blue but I still cannot start it.
I tried it with java blue ( in the subfolder bin of blue) and with java -jar blue, without success!

Hello Mr. Stefan,
You need to have java installed.
Then You only download Blue from its site

and unzip in a convenient location,
then You can start Blue from the folder blue/bin/blue.

hope a little help,