User @Autumn reported the same bug September 22. There doesn’t seem to be a solution since the previous reports of this bug. I’m using Windows 7 Enterprise with SP1, 64-bit.
As @Franksalinas reported, the project seems to load. However, I can’t tell if any elements are missing. (Because I don’t have a Mac, I can’t use Sketch to view the original Sketch files.
Also, there’s a typo (“openning”) in the message header.