mkdir /? in a cmd.exe in a Visual Studio 2005 command prompt window 
gives a usage example with backslashes.  mkdir /? in a cygwin window 
gives an error message.  But I'd like to see ntwhich in any case.

Maybe this should be renamed VS2003/VS2005 environment differences?  
Here's another one:  hcw doesn't exist in VS2005 so the leash help 
doesn't build.

[mayer@ntp.isc.org - Thu Dec 20 22:37:25 2007]:
On an advisory note try running ntwhich on mkdir and see where it
finds it. That may tell you why you are having a problem. If you need a 
copy, send me mail. I have a bunch of tools like that which are not 
cygwin based.