For everyone interested: I solved the problem, reading a similar problem posted by another fellow.
ORBD didn't work in my environment, because there was a file named orb.properties coming from a previous JacORB installation.
The orb.properties was located in my user home directory, and it conflicted against ORBD tool.
I removed the file and then ORBD worked as expected.
In other words, ORBD doesn't need an orb.properties file, but it can't work if there's an incompatible orb.properties already existing in a strategic location, as the user home directory.