Insight Reports Custom Object Error

I am trying to create an Insight report using data from a custom object. I have already added the fields from the CDO to the insight report and the data inside the CDO is mapped to contact as well. I tried using the "Contacts" and the "Contact Lists" subject areas for this and both of them give me the same error.

If I pull a contact field, say email address, from the criteria tab and then go to results, the system gives me data. But once I start adding any fields from the custom object I want to report on the results tab gives me the following error - "Error during query processing (SQLExecDirectW)"