Use the period close exception reports to identify transactions that have not been fully processed, and that would prevent you from closing a PA period or a GL period in Oracle Projects. These reports are commonly used when you are preparing to close a period. When the exceptions are corrected, the period can be closed.
You can submit each of these reports from the Submit Request window. Include the prefix "EXC:" when you enter the report name. See: Submitting Requests.
Other Sources
Defining GL and PA Periods, Oracle Projects Implementation Guide