Hello, Tupy...!

Tuesday, June 25, 2013, 11:51:22 PM, you wrote:

Tn> We repeated the action = we take the DB, checked the content of this colum 
Tn> (all lines having 0 at this column), then we run a backup and imediatelly a
Tn> restore, and we reproduced the problem (it ocurred when restoring).

If restore gives error like that, the simpliest way is to check data
in the table like
select * from table where field is null.
You will see, are there nulls, or 0.

And, since restore gives an error, that means you still work with the
same DB, which was successfuly created or restored some time ago.
When was it?

Have you compared database scripts (isql -x ...) of the current DB
and from the last restorable backup?
Are these scripts identical?

I really doubt about things when someone reports the problem,
and also says "we never do this and that". While "this and that"
usually are the cause of that problem.

p.s. of course, the source of the problem can be with a strange
database or backup corruption, but THAT kind of corruption
looks very uncommon.

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