It seems that you are having some issues with your Slingbox SOLO since the on-screen message tells you about an error message.
This error message is related to the cables you are using to connect the TV set to your cable box or satellite receiver. Keep in mind that the Slingbox will stream the signal it gets and in this case, the Slingbox has nothing to do as any possible root cause.
I recommend you verify the cables in use to get the TV set-Cable box connection. Since you are using a HD device, I encourage you to use the Component (RGB) cables and test the connection one more time.