I seem to be having the same problem that many others using Social Connect are having and I haven't been able to find a forum with a solution and neither has Brent written anything about this.
I have installed social connect and all the buttons seem to be working okay except the twitter authentication is sending back an error. The Twitter sign in seems to go through but the page after that goes to a 404. Do I have to create a dummy email address for twitter in our admin for this to work? I have enabled read&write option for the twitter auth file an I have also enabled the "Read, Write and Access direct messages" option for twitter application.
Please scroll down to look for the twitter button in the comments section. I'd appreciate if someone can help me with this and provide a solution! :)