A bit late in the day but if anyone is still seeing this then can you try this:
Uninstall Silverlight from your PC and delete the playready folder which can be found via C:\ProgramData\Microsoft\PlayReady exsists.
Note: This folder might be hidden on your PC, if so in explorer select Organize->Folder and Search Options->View->Show hidden files and folders and click OK.
Next delete the "is" file which can be found via:
XP C:\Documents and Settings\”Username”\Localsettings\AplicationData\M
Vista C:\users\”username”\AppData\locallow\Microsoft\Sil
Win7 C:\users\”username”\AppData\locallow\Microsoft\Sil
Win 8.1 C:\users\”username”\AppData\locallow\Microsoft\Sil
Win 10 C:\users\”username”\AppData\locallow\Microsoft\Sil
Mac: HD > Library > Application > Microsoft > Silverlight
Then reboot the PC or Mac and try again to use Sky Go.