Sounds similar to problem that has just developed on our JVC GR-D70U camera. Says Lens Cap even when the cap is off. Can't see anything through the LCD or view finder other than menu type items. The LCD does work fine in playback mode. I have see some comments about a known defect or something but not sure if that is what this problem is.

Got the same problem, havent used camera for about 4 months,it was ok then but not now, let me know if you get any advice, i'm still searching!!