Forum OpenACS Q&A: ns_pam download
appears to be dead.
Sourceforge appears to have a rather exhaustive collection of source for aolserver:
unfortunately, ns_pam is not among them. I have the source for ns_pam and would be more than happy to pass it along to the powers that be so it can get loaded on sourceforge and have the link fixed.
Could you add it to http://openacs.org/storage ?