How to resolve data integration error Essbase Error(1019026): Unknown member [Entity]?

Summary: I am creating a new Data Exchange integration in a source cube in a planning application (epm2) to extract data and load it to a target cube in another application (epm4).

When I run the integration I get the following error - "Cannot begin data load. Essbase Error(1019026): Unknown member [Entity] found while processing string [Entity]"

Here is some additional information:

1) When creating both Planning apps I renamed the Entity dimension to "Office" (something I've done before) so there is no "Entity" member name (I realize it is still an Entity type of dimension).

2) I have confirmed that the Dimension Classification and Data Table Column Name in both the source and target Data Exchange applications is Entity/ENTITY.