This error message usually appears because an existing DECODE calculation based on Person Status treated all data as a number. As Person Status can be a number of characters (e.g. 1, 2, A, Z etc.) a mismatch of datatypes existed.
There are two options to resolve this issue:
Option 1
Add single quotes to the DECODE calculation so all data is treated as characters and not numbers.
E.g. Update this calculation:
DECODE(Person Type, 1, Balance, 2, Balance, 'A', Balance, 0) to
DECODE(Person Type, '1', Balance, '2', Balance, 'A', Balance, 0)
Option 2
Systematically remove the columns and see which column is causing the issue. If it is a large report, do it in batches to narrow it down.