I recently tried downloading an open source program to use the haXe programming language. The program was from the official haXe website, http://haxe.org, so it wasn't simply a fake download from somebody else, but it is considered dangerous enough to be deleted on sight regardless of the user's wishes. The site is very detailed on the content, and there are active forums that can be joined, which leads me to believe that the program is legitimate, but I am also aware that, should this be a virus or spyware of some sort the results could be extremely bad, especially since the creators are apparently very smart.
Is there any way of getting definitive proof one way or another, without risking my computer or information by turning off the antivirus for the download?