I would like to thank all of you.
Since the general suggestion was that the problem was in the copy methodology and not, as I supposed at the beginning, in the firebird server settings, I did use my original program to install itself + the database + firebird server on my SERVER computer.
Since then everything started to work properly and without any error.
I don't think that my problem solution perhaps will help anybody since it was very peculiar but I'm very greatfull to everybody since I didn't have much time to learn firebird configuration or procedures.

my very best

G

--- In firebird-support@yahoogroups.com, Ann Harrison <aharrison@...> wrote:
>
> On Fri, Nov 23, 2012 at 3:44 PM, gigi_la_trottola <gigi_la_trottola@...
> > wrote:
>
> >
> > So now comes my problem, from the 3 computers I can access to the server
> > and the connection with database start properly, but after few seconds I
> > get the 3355434 error (BLR something something) and I cannot do anything.
> >
>
> Could you give us the message text? The numeric code is not easy to check
> because the message file is not text and the text files just have the
> message offset from a predefined starting point. Firebird is the open
> source version of InterBase. InterBase was written to be compatible at the
> call interface with the DEC Rdb databases, so it used the same message
> codes. DEC divided the error message space of its VAX products, giving
> each a distinct header - in hex. That's why the message numbers are so
> very strange. Of course, in the source, Firebird keeps only the offset -
> not the header.
>
> Good luck,
>
> Ann
>
> P.S. Your problem is almost certainly in the method you used to copy the
> database. Use gbak to backup the good database and restore it where you
> want it. Still, knowing what message you got would help.
>
>
> [Non-text portions of this message have been removed]
>