You said that copying cmdproxy.exe into a different directory made the
problem go away -- can you try to figure out what is it in this
particular directory that triggers the problem? Is it the fact that
there are other executable files there? the particular location of the
directory in the directory tree hierarchy relative to the drive root?
or maybe the fact that there are sibling directories from the Emacs
distro? or does the directory have some special access rights (e.g.,
you unzipped the archive as a privileged user)? If you unzip the
distribution again in another place, does the problem happen there as
well?
Btw, did you run addpm after unzipping the archive? And which unzip
program did you use?
(I can program around "Access denied", but I'd like to try to
understand the cause before that.)