>
> Here are more info that I got just now. Hope this can be useful:
>
> 1. The error message is: operating system directive CreateFile failed

Do you know whether it was Firebird or your service that had this
error. Could be permissions etc. Note also that in Windows CreateFile
is not always creating a "file".

>
> 2. The application using the database is a service. Everytime when the
> computer is rebooted, the service can't start because of this error.
> But after login and start the service manually, it works fine.
>

Is your service started by Windows prior to Firebird? I am assuming
Firebird is installed as a Service not as an Application. As in have
you declared Firebird as a service your service depends on? If not,
your service will have to take into account the fact that Firebird may
not yet be running.

Adam