Burger :
One other possibility is that there isn't 15.2Mb of disk space free. You may have somewhere, but not in the temporary download directory which IE uses. It ALWAYS puts files here before moving them to the directory/folder you specify when downloading the file.
First, check Tools -> Internet Options -> General tab's Temporary Internet files setting. Check the disk directory it refers to, and ensure that disk has enough space.
If it does, then I dunno what the problem is.
If it doesn't then either clear disk space to make room or change the Temporary Files folder to a disk which has space.
I found this out the hard way - getting 13Mb of 600Mb downloaded even though IE persisted in downloading the entire 600Mb and throwing away 587Mb of it !