CA cert error when setting up git submodules on PPC Mac 10.5.8-Collection of common programming errors

I have a git repository with submodules on github, when I try and set up the submodules locally by doing:

git submodule init
git submodule update

I get this error:

error: SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed while accessing https://github.com/wincent/Command-T.git/info/refs

fatal: HTTP request failed
Clone of 'https://github.com/wincent/Command-T.git' into submodule path 'dotfiles/vim/bundle/command-t' failed

I understand that this is a problem with the CA cert being out of date for Leopard, I have tried to rectify this by first installing a new version of curl with ssl support (now on version7.22), and then when that didn’t work I updated my crt as per instructions such as: http://www.simplicidade.org/notes/archives/2011/06/github_ssl_ca_errors.html

I still get the same error.

I’ve also tried adjusting the protocol in .gitmodules to git from https but this makes no difference either. Any ideas?