You didn't share what program this was, it's web site and more.
But if you want to press your luck, MOVEONBOOT can delete the file in the target directory, as well as move it on another boot.
No one knows the end result yet.
I downloaded an update to a small program. Then I went into "My Downloads", right clicked, clicked on Send To, clicked on my A drive, it gave me the screen about the file was already there and all the info about its size and date. When I clicked on the button to replace the old with the new file I got the yellow triangle with the exclimation mark saying "Explorer has caused an error in <unknown>. Explorer will now close. It goes on to say that if you contunue to have the problem just reboot; whick I did several times and still had the same problem. I tried going through Windows Explorer by dragging it onto my A drive and got the same error.
How can you fix it whith the "error in <unknown>."