This is the first time that this error has come up. I am using Cygwin with Eclipse 3.5 and my Path variable is set to: %CommonProgramFiles%\\Microsoft Shared\\Windows
I had same problem and I solved that copy make.exe file in path that ecilipse given.
from link below
http://www.mediafire.com/download/e9j9g4zun2t68jn/make.exe
hope helps