You obviously have not read the forum rules! You are not allowed to mention files (file names) you download at this site. Also you have not provided enough details.

Firstly, you did not give us the type of file you downloaded. Is it an mpg or wmv or something else. There is a freeware program called VLC by VideoLAN that will play wmv, CD, DVD, VCD, DivX/MPEG-4 on OS X. It doesn't have the best controllers but at least it's free & it's cross-platform! You can find it at most mac shareware sites or do a web search for it. If QT can't open it then try VLC (previously known as VideoLAN.)