I would try an alternate method of performing the setup if it continues to fail on one way.
Web Slingplayer for Internet Explorer, Firefox, or Safari (http://watch.slingbox.com)
Slingplayer Desktop for PC (http://support.slingbox.com/go/windows-download-desktop-us)
Slingplayer Desktop for Mac (http://support.slingbox.com/go/dl-mac-desktop)
I just now completed my first successful setup. The variable was selecting the channel provider. Despite it being Verizon FIOS - I chose the local cable company instead. I can then manually match the digital channels to local networks in the guide. This is a workable solution, not ideal. It must be some sort of error with the guide data/channel list with the FIOS setting.