A beta installation at one of our client's facility is failing to
connect. After consulting with them, their IT department opened the
3050 port on the firewall to outgoing traffic. This has not solved
the problem.

They have copied the application's exe file, fbclient.dll, and
gds32.dll files into a single directory that they launch from.

My application opens, the user puts in his user id and password, but
then gets the following error message as the application attempts to
connect to Firebird:

*************************************
ISC ERROR CODE:335544721

ISC ERROR MESSAGE:
Unable to complete network request to host "###.###.###.###".
Failed to establish connection.
No connection could be made because the target machine actively
refused it.
*************************************

Note: I replaced the IP address with ###.###.###.### for security
reasons. Thae actual error message provides the IP address.

Beta tests at other locations have worked fine. Any sugggestions?