Hi! I have seen the link you have sent me, but I have also done all that (Restart, download it again etc) and it still won't let me open it. Thanks for the help!!
The first three options (restart/redownload etc.) there won't do much. If anything helps, then the fourth option with xattr. The comments below also go into a bit more detail and give a few tips that can help better. But sorry to hear it didn't work out!
