Hi Warren,
This is so odd I don't even know how to respond. Your view is flumoxxing.
I'm going to invoke Mary Cooch, who is @Moodlefairy and also ask if you are comfortable letting someone from outside your Moodle have a peek into your Moodle. If so, use UsingMoodle to PM either Mary (who is much bettter at this) or me with your login info.
It may be that your particular theme substitutes "users" for "participants." I do not know enough about themes to easily identify a theme that might do that.
I'm in Baltimore. I'm about to -- finally -- eat dinner.
If you haven't resolved your problem in timely fashion, email me a nudge @ ben.reynolds@jhu.edu
I've been on the web so long that spammers also use my address, so, if you get an email from me and it looks suspicious, delete it. Look for a useful subject line. If you think it is bogus, it probably is.
L