CL returns fatal error on some directories

[Empyreal96]

NMAKE : fatal error U1077: 'cl' : return code '0xc0000135'

This occurs with some folders in the tree, a quick search told me it's to do with cl.exe not being in the path.
I have a few guesses as to why:

• Headers and some source files were taken from Windows 2000 DDK and Platform SDK, so some source and makefiles may need tweaking.
• As the reason above, VC98 and DDK paths may need to be added to the Build Env to satisfy some issues
• Missing files e.g mspdb60.dll