Select Language at Signup Plug-in Not working

I have a question about "Select Language at Signup" plug-in. I am running "S2 Member" and I can't seem to get this plug-in to work. I don't know if it is not compatible with "S2 Member" or I installed it wrong. I tried everything I could think of to get this to work, even read though the documentation 20 times to make sure. I am not getting any error messages, just nothing shows up during sign up.

I also would like to know if this plug-in will allow users to change the selected Language later.

Thanks!