Issues Using Search Module

Our client is using DNN They are using DNN Ver: 06.01.05 (142)., they have a dedicated VPS, and are not in a Web form. The basic issue we have is that we can't search imported users by their first or last name in the Admin > User Accounts module. Searching by email address works fine.

We imported several thousand users from their old DNN site to a new one we setup. Through our testing we have come to see that if we update a user/profile in any way, that user is then searchable by all fields, not just their email address.

So the question is ...what do we need to do to get all of these imported users to be searchable. Obviously we need to do some kind of update of some kind on the portal so that they become recognized by these additional fields. What we need, if you can tell us, is how we to do some type of a global update that would affect all users. Or even some other method to either script or automate making an update so all fields are searchable.