The %Path% variable contains exactly that: the *path* ("C:\NMake") to folders that should that should be searched, *not* single executables ("C:\NMake\nmake.exe").
In addition, the system paths should always be listed first.
Try this:
%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;C:\Program Files\Common Files\Roxio Shared\DLLShared\;C:\Program Files\Common Files\Roxio Shared\DLLShared\;C:\Program Files\Common Files\Roxio Shared\9.0\DLLShared\;C:\Program Files\QuickTime\QTSystem\;C:\MinGW\bin;C:\Program Files\MySQL\MySQL Server 5.0\bin;C:\Program Files\Common Files\Sage SBD\;C:\Perl\bin\;C:\NMake
Once you've corrected the path, open a new command prompt to test; changing the path does NOT update the variables in shells that were already open.