VB won't run downloads

[Robot]

I have downloaded Virtualbox into my windows 8.1 and using windows xp as the guest and all downloaded well and ran all the the program included the extentions.
I created a Virtual share folder in the host (Windows 8.1) and loaded the files that are to be copied to the VB (xp).
I created the share program in vb and transfered files to vb from host all seems ok so far .
Now the problem I have is all the transfered files are slow to respond and the downloads won't run in vb.
So I downed the drivers directly from the website and the downloads won't run in vb.
So on closer look I noticed that the downloaded drivers were only part files downloaded from the websites therefore they won't run or load into vb.
Is there something that I have missed or is there something blocking these downloads into vb.
Can someone assist me in this area please.