Hi David,
OK so this is unclear, and I don't recommend using SELECT statements in SQLExpressions but others here say it should work... Anyways I would think it's the fully qualified names causing the problem since that is the error being generated by Oracle:
Try wrapping all of the references in double quotes, not just the field.
"INNERALIAS"."EFFDT"
It could be, assuming you are using ODBC, use Quoted Identifiers in the ODBC properties is not checked on, again assuming you are using a driver that supports it.
As a test copy the SQL and create a new report using a Command Object as your data source and see if that works...
Does that SQL work in SQLPlus?
Don