I have the exact same problem.
It is a Sharp tv with 1080i. No HDMI input. Slingbox 500 worked great with it when I had a Comcast DVR input. Now with FiOS ARRIS ipc 1100, I get this Blue screen: "Not Compatible with this signal."
Using the component cables from Slingbox.
Here is something weird. See the picture perfectly during setup (though in a small window.)
Worked fine on the internet, just not on the tv screen.
Connecting box directly to the tv - picture is fine.
Just wanted to let you know if your Sharp TV is not a HDTV, the setup through that TV will not work.
Some TV's have the capability of having component connections to them but are not true HDTV's. This could be the reason why you are getting the "Not Compatible with this signal" on your TV screen.
Hope this helps!!!
Sling Media Moderation Team