I created a brand new user and noticed that XOOPS recognized the name, etc. so I looked for any difference between that new user and the existing users in my database.
Previously xoops_user_profile had zero rows. When the new user signed up, a line appeared, with the correct new user's profileid #. Since my user base is small for my website, it was a piece of cake adding a minorly modified Query this:
INSERT INTO `xoops_user_profile` VALUES (1, '', '', '', '', 1124296823, 0, 0, '', 1, '0', '2281f22d', 1124299035, '
', '', '', '', '', 0, '', '', '', '', '', '', '');
Copy this line for each user, Replace the FIRST 1 with the profileid #.
Careful - It made everyone a "registered user" level, even former Admins were back to "registered user" too.