find-dired + windows + (gnu) find

[md3bs]

I am trying to search and replace on multiple files using regex.

I have no problem using %-m after calling C-x dired. However, when I %-m 
after running find-dired I get the following error message:

dired-get-filename: Invalid escape character syntax

I am using emacs out of the box with only one change:
; The gnu find program ( renamed )
(setq find-dired-find-program "gnufind.exe")

The actual find command that is run is
 gnufind.exe . \( -name "*php" \) -exec ls -ld {} \;