> I'd encountered this error while opening the FDB file sent by client
> using FB 1.0/1.5/2.0/2.1;
>
> Statement failed, SQLCODE = -820
>
> unsupported on-disk structure for file C:\SK.FDB; found 523, support XX
>
> So I think this ODS ver is not supported by any available firebird
> release.

Are you sure you have Firebird running ? Looks like Interbase...

Regards,
Vlad