Problem with ejabberd-2.1.11 on Windows XP

I'm doing some testing with setting up ejabberd. I am installing it from the installer binary on a windows XP SP3 system. I can get ejabberd to install, but the postinstall script shows an error - it can't register the admin user. I get the same problem when trying to register users manually from ejabberdctl. It does seem to create a windows service, but the windows service won't start (I can start it from ejabberdct). The service gives a system error "Erlang machine stopped instantly (distribution name conflict?)".

No log files are being created, other than the install log.

I've tried uninstalling and reinstalling, making changes to the config file, rebooting the system, and similar trouble shooting methods.

Anyone have any ideas about where to look next?

Thanks!