I\'m using gvim on Windows.
In my _vimrc I\'ve added:
set shell=powershell.exe set shellcmdflag=-c set shellpipe=> set shellredir=> function!
Try replacing
"dir \*vim\*"
with
" -command { dir \*vim\* }"
EDIT: Try using cmd.exe as the shell and put "powershell.exe" before "-command"