I am using the following to create and edit environment variables for Windows 7.

Control Panel\All Control Panel Items\System -> Advanced system settings -> Environment Variables

Under System variables I have the following pertinant variables:

PROG32=C:\Program Files (x86)
REALDWG_SDK_DIR=%PROG32%\Autodesk\RealDWG 2011
Path=%REALDWG_SDK_DIR%;%PROG32%\Haskell\bin

However, the following happens:

C:\>echo %PROG32%
C:\Program Files (x86)

C:\>echo %Path%
%REALDWG_SDK_DIR%;C:\Program Files (x86)\Haskell\bin

Is it possible to have a chain of variables expand?

If I rename Path to something else, I sometimes get the problem, and sometimes I don't.