Just helped someone else figure this one out. Try using a different browser. That message is coming from Amazonaws.com, could be an add-on. If it works, like it did for us, on another browser, then that's probably what's going on. Research how to remove add-ons from your particular browser to prevent any further problems with other sites. Also, try doing what you're doing from outside of SL, using a different external browser. Good luck! ; )