Go to your Bootleg.exe, right-click open Properties, and under the Compatibility tab check the box "Run this program as an administrator". Then click Apply and OK.
Hang in there and try not to stress too much. These errors have been posted before and usually come up with solutions. Just keep reporting back here 
Afraid it's the same story there. I've decided to give up with bootleg for now, I can't seem to get it to give me anything other than the Access Denied error even with running as admin and non-system folders :/
I have however successfully manually modded the game although not to the exact specifications that I wanted from Bootleg. But Beggars can't be Choosers I suppose!
Here's hoping Bootleg 40 does the trick!
Edit: I mean I can get the game to run without bootleg, and I can get the game to run if I mod it myself, but I can't get it to run with bootleg, so I don't know if there's a compatibility issue with 64 bit systems or if there's a problem with some Mods in there. But I do get the Access Denied error if I try to run bootleg with no changes. I've also made sure all of my folders have full permissions granted - all to no avail