If I disconnect from WiFi and submit my PIN over 3G, I am successful. I'm using Open DNS for my home network (not sure if that makes a difference, but I've seen it mentioned in some older posts regarding similar connection issues).
Yes, opendns is the issue. They do not fail properly if dns doesn't resolve, instead they send you to an advertising page. I believe you can set wikidsystems.net as a domain that does not get redirected as an opendns user. If so, please post the details.