PAY: pay_balance_pkg function returns ORA-14552 error

I have a need to spin through employees and check deferred comp and HSA contribution balances, compare to the YTD limits, then export a list of staff who are nearing the YTD limit.

I wrote a PL/SQL package using a cursor to drive off employee run results for the as-of date desired and the elements involved, then for each employee returned, it uses the package pay_balance_pkg.get_value(<balance id>, <assignment_id>,<date>) to find the balance.

I am getting a sporadic error "ORA-14552: cannot perform a DDL, commit or rollback inside a query or DML".  I had an employee whose first paycheck was on pay-period-ending date 08/13/2012, check date 08/17/2012.  When I run the procedure for as-of date 08/13/2012, it errors on that employee.  If I run it for as-of date 08/17/2012, that employee does not get an error.