You must be using Minilogin. Minilogin tracks accounts by IP, and not username or password. That's why you keep logging into the same account no matter what credentials you enter.
It may be possible to work around this. I couldn't get it to, but try this post:
http://www.eqemulator.org/forums/showthread.php?t=25898 You may be able to get it to work.
There are other ways to set up a login, either by using the EQemulogin.exe or simply changing your eqhost.txt and eqemu_config.xml files to point to the EQemu login server.
I'm not sure about any solo instances. Must be some expansion after PoP, and PoP is the highest I've ever gone.