hehe, this is the message i now get on winxp using the "old" gcc 3.4.6 toolchain. i dont know how to fix it 
Both, the gcc 4.3 and the 3.4 works fine here on XP (trunk #652, #654) - as usual...

Can you both post your
path environment variable ? (e.g. with path > 1.txt in a cmd window)
Looks like there is something wrong...for the CHDK-Shell there's no need to edit the path manually, it appends the gcc\bin path automatically at the beginning of the path (only for processes started by the CHDK-Shell).
Hint for the gcc 4.3 environment by wim: if you have a Cygwin environment already installed, you must disable cygwin mounts first !
(i.e search in regedit on string "cygnus" and delete both keys, 1 in HKCR, 1 in HKLM (if you need them still, be sure to export the keys first))