Hi,
This is a member of the Viber Development Team
@shanfoley - When this happens it is due to a connection issue, and jailbroke iPhones (this usually has to do with the device's push notifications). This error seems to be more relevant to iPhone 3G which is not a multi-tasking device. If Viber can't make a 'stable' connection with the server, or if the device is unlocked/jailbroke, the process will not continue. You may try again later. If using 3G, try WiFi. We have also heard from many users with jailbroken/unlocked devices, that a third party application, such as push fix app. has proven to solve this issue. We have not tested this, and cannot confirm this for sure.
Please feel free to let us know your thoughts, questions and comments.
Thanks,
Viber Team