Re: aggregating error with Cardinal(54), for Object
Guess you have a rather detailed and big data-model and aggregates on a bunch of dimensions in your pivot-table.
First look through your data model. Possible to reduce number of distinct values? Need the low level? Change keys to being numeric. Put the dimensions and the facts in the same table if possible to avoid big "joins" at runtime.
I've seen this warning with a suggestion to use a new "row-applicatior".