I am using 3.1.1 and it appears as either your plugin is not working or your configuration tutorial has not been modified to work with the latest version of multiuser.
I have uninstalled the plugin and I have set everything up.
My sites seem to work fine except I am unable to login as SuperAdmin on my other sites.
I have been able to successfully redirect the sites WITHOUT using your plugin except I have had the superadmin login issue.
I am using *.mydomain.com wildcard redirects and I am using the latest (fresh) install of wordpress 3.1.1
any advice would be greatly appreciated!