Thanks to GP so much for that query!
I was able to ferret out the context ids from the URL in the browser when manually enrolling users. My first course is context 14 and my second is 26, for whatever reason.
I'm not getting anywhere with the enrol ext db plugin. It just doesn't work, or log useful errors, and it's holding up my project and frustrating me.
So it looks like I'll be manually updating the mdl_roles_assignment table some way, which does work.
eg: mysql> insert into mdl_role_assignments (roleid,contextid,userid,hidden,timestart,timeend, timemodified,modifierid,enrol,sortorder) VALUES (5,14,10,0,NOW(),0,NOW(), 2, 'manual',0);
seemingly enrolled a user in a class which the enrol cron seems to have never done. Pardon my SQL.
Hope that helps you some,
Notice: weird! no user record entry? in /home/.flash/atlbbs_sysop/atlbbs.com/classes/enrol/database/enrol.php on line 342