Doesn’t work for me and that’s coming from a fresh unmodified installation. The issue is that the error “please enter a username” pops up upon each attempt to register meaning that it didn’t post which in turn causes your php file to send an empty string to Minecraft that returns false so you also get “not a vaild minecraft account”. When I disable the plugin, I can register as usual. I was really excited about this one… I’ll be watching to see if it gets a fix.