Some of you have been experiencing problems with reaching the website when checking in or paying for a system. It appears that something is blocking the connection. I think I have it mostly figured out, at least I am able to connect now myself. For now the solution is to install or update to the latest version (2013.10.08).
Update (2013.10.15):
My webhosting service has been blocking the connections because they have a similar signature to that of a new botnet. The solution I came up with above is the preferred long term solution (upgrading). For the short term they have turned off their botnet security on the affected urls. However, they will be turning the botnet security back on on November 1. You must upgrade to at least 2013.10.08 by then. Sorry for the inconvenience.