Hello, Tupy...!

Wednesday, June 26, 2013, 12:35:34 AM, you wrote:

Tn> I will not repeat (ooops, I am already in the way !) that the
Tn> source DB (for the backup) is ok.

currently no evidence that it is ok :-)

Tn> GBak ! This mean = or the problem happens at the backup process, or during the restore
Tn> process.

usually process is
- backup see data, store it
- restore creates metadata, restores data, data does not fit to
constraints - error.

Tn> But as we have no tool to see the backup content, it´s
Tn> not possible to know where

It's possible. Tool name is IBBackupSurgeon.
You can dig in that direction, too.

Tn> We experimented to restore first only the DB structure and then
Tn> restore the data, and then we got no error. Using the same backup file.

You can't do that. You can restore metadata+data or only metadata.
Gbak is unable to restore data into existing database.
So, please explain what you are doing.

Tn> We have FB 2.1.

this is misty. I know 5 versions of 2.1. 2.1.0, 2.1.1, 2.1.2...
and all of them up to 2.1.4 have bugfixes.

--
Dmitry Kuzmenko, www.ib-aid.com