I just downloaded this file.  It unzipped and played fine, no passwords, no weirdness.  Other mediafire files work fine also.

So two suggestions:
1. Update your zip software.  If you're using the freeware program 7zip (available from downloads.cnet.com), be sure you have version 9.2 or later.  The earlier versions don't work for this.

2. If you still have trouble, the most common problem is hitting a Windows path limit for characters.  Zip facilities sometimes create an extra folder within another folder and it can be enough to put you over the top of that limit.  When that happens, things don't work but Windows doesn't generate any error messages.  The fix is to create a temporary folder near the root of the drive you are using, like c:\temp.  Move the file(s) there for joining and unzipping, then the finished product can go back to your video folder.

Also, if you are using 7zip, you can avoid this problem by the following:
1. Highlight the file or files to be joined and unzipped
2. Right click on the highlight and select 7zip "Extract Here"
Enjoy

That way you avoid all the extra folders being generated.

If there is still a problem, try PeejeShare if it is available to you.  Where I live, it's faster than mediafire, and no unzipping involved.