I keep getting REP-0498: Number of columns selected by the query is incompatible with report definition.

I have changed the backend definition of the materialised view that I am using and re-compiled my report, and saved it. This is not working. I've still not managed to run my report without getting this message.

I even recreated the object in the data models and set up all of the summary CS and CFs again.

Still din't work. I'm so frustrated now.

Please can anyone help?