I followed the suggestion in Brian's comment and it worked!
I downloaded setrefs.c v1.63, copied to the postsql src directory in the src/backend/optimizer/plan subdirectory. I recompilied postgres and installed it. I then killed postmaster and shut down the nsd server for OpenACS. I restarted postmaster and the nsd process. I retried the intranet and did't get the previous errors or any additional new ones (as far as I could tell).
Note I didn't use the most recent setrefs.c as it had a comment that one needed to do an initdb. I used the next to most recent. I didn't reload the data model at all. Everything seemed to work fine with my previous data.
