I didn't succeed installing the two versions of postgres.
For installing I am running the "configure" script as follows:

./configure --prefix=/usr/local/pgsql-7.4.5 --with-java --with-pgport=6947

Although I specify a different port than the default one, the postgres it is
installed with the
default port. The port must be specified also in another configuration
files?

Regards,
Loredana