OK, the architecture is 32-bit, but it's a Mac G4 (PPC).
Both the Darwin flavour (Mac OSX 10.4.11), and the Debian distro I just installed, come up with the same error.
Unfrotunately I do not own or have access to a Mac so there is no way for me to verify that the keys transacted during the login process are calculated correctly.
What you would need is a test suit to run the calculations on a Mac and on a platform that is known to funciton and verify that the results of the calculations are the same.
I am not sure how to write such a test suit.