The "narrowed down" version needs some attention. First, all the data the avatar matrix program needs it gets from this query. So...since avatar is a field in #__comprofiler, that means that #__comprofiler must appear in the query. Second, since multiple tables, each with multiple fields, appear in the query, each table needs an alias. That way we can append the alias to beginning of each field, and SQL knows what table the field belongs to. To give a table an alias, just put the alias behind the table, with a space between. Third, we're getting data from three tables, so we have to join the three tables on the data column that contains their user id, jos_comprofiler, jos_users, and the Simpleboard table. That way we know whose karma matches up to whose avatar, even though these data are in different tables.
Try this:
SELECT u.username, u.id, c.user_id, c.avatar, sb.karma, sb.userid FROM #__comprofiler c, #__users u, #__sb_users sb WHERE c.banned='0' AND sb.karma>0 AND (u.id = c.user_id) AND (u.id = sb.userid)
I can't remember the feature set that's in .4 exactly, but if some other fields are being captioned above or below the avatars, just leave these fields blank for now.
Raj