Hello,
Whatever I have checked in this function module that there were not exception handling. So, you will not been able to understand what went wrong. But you can check a sy-subrc after your function module so, if it is NE "0" then keep the records into internal table and at the end of the loop you will be able to see the records which are not parked.
Please let me know for any further concern.
Thanks & Regards,
Abhijit