Weird problem with compiling AtMega_Board_Programmer & ...Detector

Using Windows 7-64bit and Arduino IDE 1.0.1
After downloading and compiling in IDE 1.0.1, 2 sketches: AtMega_Board_Programmer & AtMega_Board_Detector from Gammon Forum : Electronics : Microprocessors (An excellent WEB SITE by Nick Gammon!!)
I would receive similar errors as seen below. In an attempt to solve the problem I renamed the md5.c sketch to md5.cxx, a recompile gave no errors and the programs ran as described! However the next day I tried the compiles again with a new error md5_starts' md5_process' md5_finish' md5_update' not defined....
I then renamed the md5.cxx back to md5.c, again got the errors below then renamed md5.c back to md5.cxx, with everything working again.
Now for the good news, I installed IDE 1.0.3 and now do not have to go through the renaming process. Things work each and every time from both the 1.0.1 & 1.0.3 IDES with these sketches. Did the installation of 1.0.3 fix this?? Who knows? If you experience a similar problem and determine the exact cause, please share...

AtMega_Board_Programmer\md5.c.o: In function md5_starts': C:\Program Files (x86)\arduino-1.0.1-windows\arduino-1.0.1\libraries\AtMega_Board_Programmer/md5.c:40: multiple definition of md5_starts'
md5.c.o:C:\Users\DECTER~1\AppData\Local\Temp\build1068337284599769117.tmp/md5.c:40: first defined here
AtMega_Board_Programmer\md5.c.o: In function md5_process': C:\Program Files (x86)\arduino-1.0.1-windows\arduino-1.0.1\libraries\AtMega_Board_Programmer/md5.c:51: multiple definition of md5_process'
md5.c.o:C:\Users\DECTER~1\AppData\Local\Temp\build1068337284599769117.tmp/md5.c:51: first defined here
AtMega_Board_Programmer\md5.c.o: In function md5_update': C:\Program Files (x86)\arduino-1.0.1-windows\arduino-1.0.1\libraries\AtMega_Board_Programmer/md5.c:174: multiple definition of md5_update'
md5.c.o:C:\Users\DECTER~1\AppData\Local\Temp\build1068337284599769117.tmp/md5.c:174: first defined here
AtMega_Board_Programmer\md5.c.o: In function md5_finish': C:\Program Files (x86)\arduino-1.0.1-windows\arduino-1.0.1\libraries\AtMega_Board_Programmer/md5.c:221: multiple definition of md5_finish'
md5.c.o:C:\Users\DECTER~1\AppData\Local\Temp\build1068337284599769117.tmp/md5.c:221: first defined here

Right then. I just went to a Windows 7 PC that I don't normally use. I downloaded IDE 1.0.1, and the Atmega_Board_Programmer zip file from:

Note different capitalization from your post, I'm a bit puzzled by that.

After mucking around copying the (unzipped) .zip files onto the desktop (Arduino and the Atmega_Board_Programmer folder) and answering some ridiculous questions from Windows about "are you sure you want to copy this without encrypting it?", it compiled without errors.

C:\Program Files (x86)\arduino-1.0.1-windows\arduino-1.0.1\libraries\AtMega_Board_Programmer/

You should not have put that folder into libraries. My forum post said:

Download the above file, unzip it, and place the resulting folder into your Arduino "sketches" folder.

Sketches folder, not libraries folder. And you should not in any event be adding any files at all to:

C:\Program Files (x86)\arduino-1.0.1-windows\arduino-1.0.1

That is the downloaded app. Don't touch it.

Got It.