I wanted to update this thread and let everyone know I got dbiproxy running as a server. Or rather had it running all along.

It turns out that when I set the user id in Windows Services, it doesn't take effect until a reboot. After a reboot it acted as the user I specified in the Services dialogs under "Log on". I think maybe the srvany.exe tool that Windows provides spawns off a child process to run the "whatever you specify" as a service. So changing the user only changed the master process. Rebooting causes it to be that user as soon as it starts up.

Thanks for the responses.