GTA V On Demand (Unable to Launch?)

I Bought GTA V on Demand the day it was released On XBOX On Demand.and I played it off and on for awhile then moved on to other games.i recently tried to launch it after not playing it for 2 weeks and as soon as i launch it i get this prompt to insert disc?!?!?
it's on demand why is it telling me that? does anybody know how to fix this crazy error?i tried redownloading the install packs.this happened after i downloaded the beach bum update.can the updates be causing a error for the install packs they created to fix
the game install error people had with the disc?

thanks - Kal

:)

 

GTA V on demand unable to read disk

Try clearing your cache (support.xbox.com/.../clear-system-cache) and then restart the console and try playing the game again (online).

 

GTA V on demand unable to read disk

I recently bought Grand theft auto over xbox live on demand and now a new update aparently has come out and when i got to play GTA V i get the message for the update but then immediatly get an " Unable to read disk" message. I have tryed to even play it
offline with out the update but i continue to get the same message about a nonexistant disk as my xbox has no game at all in the tray as i purchased it on demand. If anyone has an explanation on how to fix this can u please explain it to me.