Hey man, really thanks for everything.

I have done what you said but it doesn't works :(

I will tell you my problem again.

I have installed firebird on a local machine and after running an
application for about 48 or 72 hours the server disconnects the
database. Why is this if firebird is in local machine?

I tried using "SERVER:C:\Path\DBNAME.FDB" and "C:\Path\DBNAME.FDB" but
doesn't works, the database still disconnects.

I'm using the same application on hundreds of customers and I only
have this problem with one. This PC has WindowsXP Pro SP2, I'm using
Firebird version 1.5.3.4870.

Thanks for everything friend.