I have a similar problem to many people in where I cannot download minecraft due to a file that supposedly already exists:

Unable to create directory. death1.ogg
Name: death1.ogg
URL: http://resources.download.minecraft.net/68/68beeda338fdb43c3b7cbbb718e82839e6d07ef3
Error details: The system cannot find the path specified
Filename on disk: 13d9-010c-bf9d-047d
Path: C:\Users\Zanscape\AppData\Local\Temp\13d9-010c-bf9d-047d
Exists: file

Long story short, it does not exist.
All of the forums that I have seen have been resolved by a program called ByteFence
I do not have Bytefence.