Calling PAM from within an SO

[Mark Valence <kurash sassafras com>]

My program loads a shared lib (.so) that then calls pam_start, etc. 
pam_start succeeds, but when I call pam_authenticate it fails with 
error "Module is unknown".

Same exact code works when linked into the main program (i.e., not in 
the .so).  Is there anything special about using pam from within a 
.so?

TIA,

Mark.