I tryed downloading it with Internet Explorer and I recieved the error message about it being corupted.
I then found a free download manager called Download Wonder and used that to download the file, I was sucessfull. I was able to install Qnx with no problems.

Download Wonder can be found at http://www.forty.com/programs/DLWonder.exe/index.htm

I didnt like it as a download manager, so you might want to search for another download manager or use Download Acelerator as previously sugested.