Ok. Sorry about the delay. I worked out the issue with the other person having troubles. It turns out he had two copies of the library code in the project, so it was linking to an older version and causing weird issues.
I checked a fresh download of the Chipmunk Pro 6.1.1 trial from the website and was unable to reproduce the issue. The method signature shows up in the symbol dump of the library as well for both armv6 and armv7 architectures. So I'm not quite sure what your issue could be.
Is it possible that you have a duplicate as well? The linker simply picks the first one it can find when searching the library paths. Just to be sure, try removing all of the Chipmunk library code from your project (including the header and library search paths in the target build settings). It shouldn't compile at this point unless it's finding a library hiding somewhere else in your project. Then download a fresh copy of the 6.1.1 trial and re-adding it.
Other than that, I'm not sure what the issue could be.