The Installer for the CAC Next Generation (a.k.a. CAC-NG) Tokend support for Mac OS X 10.5 “Leopard” was fixed and re-posted. The previous installers have been replaced with this new version - v0.96.
Support for Snow Leopard is forth coming, but you can proceed to test with your Mac OS X 10.5.6+ machines with this installation.
You can verify the installation of this new tokens “CAC-NG” by checking its existence at the following path.
/System/Library/Security/tokend/CACNG.tokend