I have a Samsung Epic 4G and received the following error when attempting to add a 2nd Google account to my phone: “Can’t establish a reliable data connection to the server”. Apparently this is a bug in Android. The work around for me was to open the YouTube application and log in with my desired Google account. After logging in to YouTube my account showed up in settings and I was able to use the account. This does not seem to work for all users, some apparently have to do a hard reset.