Hmm - nothing really without digging into this further, however, I would suggest trying Run Program As -- these two functions use slightly different process creation API's.
Yeah, this seems to be the same things.
I also figured it would be because copy, del etc. are parsed by the command shell.
I needed to add the quotes so I can use paths with spaces in them
First thing I tried btw was putting the commands in a batch file, using the Write To Text File (or something) plugin. Which also worked. Only I needed to delete the temporary bacth file after that.. for which I came up with this solution