Ok. So here is what worked for me.
1) I downloaded bobotheclown_gti's http://www.mediafire.com/download/jpvteddwwlh52t5/MCMap Live for 1.7.2.zip linked in post 521 above.
2) I downloaded mcmap v2.4.2b source from http://blog.wrim.pl/mcmap/
3) I downloaded libpng (and libjpg) from here (combo installer) http://ethan.tira-thompson.com/Mac_OS_X_Ports.html
4) I installed the package from step 3.
5) unzipped the mcmap source code from step 2, and did make on the command line
6) the new mcmap binary created from step 5 I copied into the MCMap Live for 1.7.2.app/Contents/Resource/ directory replacing the existing one.
Now it works like a charm. I think to get Bob's to work you just need to install the libpng from step 3 (speculation). It appears that mcmap is dynamically linked to the libpng library while the original mcmap in the MCMap Live 1.5.5 app is statically linked.
Thanks everyone for all your clues to figure this out.