Environment Variable Definition

Archived from groups: microsoft.public.windowsxp.general (More info?)

This is happening in my Windows-XP Professional sp2 version.

If I define some environment variable (using advanced tab on system control
pannel) that include definition of another environment variable (again
defined using advanced tab on system control pannel), such as:

HCC_USER_LIB=%HCC_SRC_ROOT%\lib
HCC_SRC_ROOT=C:\My Projects\My Source Code\hcc

sometimes dependent environment variable will use actual expanded value of
included environment variable (and in those cases variables such as
HCC_USER_LIB would evaluate to C:\My Projects\My Source Code\hcc\\lib). This
is correct and expected.

But some times the dependent environment variable would keep the included
environment variable as it is without expanding. This leads to lot of errors
while running program.

Any ideas whats happening and what to do? I can use full expanded value
itself as variable definition, but then changing some value would envolve
changing it on many variables.