Make sure that you have created a selection for the ad-hoc query you would like to use.  Any time you want to use the results from a query in another area of Altru, for instance in a mailing or in an export, you must create a selection from the results. 
  1. Go to Analysis>Query
  2. Highlight the desired query in the list and click Edit 
  3. Go to File>Properties>Options Tab
  4. Mark the "Create a selection?" checkbox