I had a similar problem. I was viewing the user list and tried to click on a user. Every time I did this, it would hang and ps would show nsd as defunct.
In my case, it turned out to be the Bookmark support. It was excluded from load-data-model.sql but was included in bookmarks-defs.tcl. My problem was fixed by commenting out this line:
lappend ad_user_contributions_summary_proc_list [list "Bookmarks" bm_user_contributions 0]
