Hi,

> I used the installer, not the zip (Firebird-1.5.1.4481-Win32):
> The service is running (or at least it says it started).
> Classic not superserver.

If you are using Classic, then try to explicitely specify
the path to the security database by using TCP/IP loopback.

For example:

gsec -database localhost:c:\path_to_security.fdb -user sysdba -password yourpwd


Best Regards,
Thomas Steinmaurer
LogManager Series - Logging/Auditing Suites supporting
InterBase, Firebird, Advantage Database and MS SQL Server
Upscene Productions
http://www.upscene.com