Analytics Software

What does this join configuration message mean? I am a user not an administrator but I notice that sometimes I get this message when I am trying to create reports in Discoverer.

Currently I have a report that is using a control table and a detail table. I need to link to another table (not a detail table). The join did not exist but I was able to take a transaction and join to the table with sql. I asked that this join be created in Discoverer so I can link to the other table in the report and it was created, but when I go to pull in the field I need I get this message:

Join configuration cannot be resolved. Reason: more than 1 of the detail folders uses non-aggregated items.

Can this be resolved and if so how? We seem to get this message fairly often.