First, with a command
$ echo _ZN5boost6detail13once_epoch_cvE|c++filt
we can see, that your boost library is missing the boost::detail::once_epoch_cv symbol. Such cryptic missing symbols are coming in most cases from c++ namespace / class names, and they could be translated ...
Dlib is not looking in the correct location for Boost. There is a workaround for this by using an environment variable (LD_LIBRARY_PATH) to tell Python how to find the libboost SO. Assuming your libboost SO has been dropped in /usr/local/lib,
There's a link to MacPorts site where you can learn how to install older port version.
However your desire to use obsolete software versions would do you no good. It would be much better to fix your app then relying on specific version of third-party application.