Searching EXE: C:/PERL/BIN/NMAKE.EXE
PKSFX (R) FAST! Self Extract Utility Version 2.04g 02-01-93
Copr. 1989-1993 PKWARE Inc. All Rights Reserved. Shareware version
PKSFX Reg. U.S. Pat. and Tm. Off.

Searching EXE: C:/PERL/BIN/NMAKE.EXE
[download]

It seems that the nmake.exe you downloaded is an archive that contains the real nmake.exe and other files. Extract the archvie and overwrite the nmake.exe you have with the one from the archive.