Now it works. There was another process connected to embedded DB.
But if I try to restore db from backup file, then DB is not more accessible.
I also tried to restore db with gbak utilities but I have this output:

>>Done with volume #1, >>"C:\NetBeansProjects\Ladon7\ladon7code\update\restoreLadonD
>>B.fbk" Press return to reopen that file, or type a new

name followed by return to open a different file. Name:

Surely I forget some parameters... it seems that restore process needs something else...

--- In Firebird-Java@yahoogroups.com, Roman Rokytskyy <roman@...> wrote:
>
> > The value of both path are correct and the db file exists.
>
> What about file permissions? Or network path?
>
> > I can't understand where could be the problem...maybe the db file is locked. But backup works also if I have any connection opened to db.
>
> Can it be that the backup file is open by the superserver binary at the
> same time? This one opens file exclusively, so you cannot connect to it
> with embedded...
>
> Roman
>