As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5607, SDF TO IAH - AT FL280 THE CREW RECEIVED AN APU OIL PRESS MESSAGE ON EICAS. THE QRH WAS FOLLOWED AND THE AIRCRAFT DIVERTED TO AEX WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE APU OIL LEVEL LOW. THE APU WAS SERVICED WITH 1QT OF BP2380 IAW 12-13-49, OPERATIONAL CHECKS GOOD, NO LEAKS NOTED. LATER ON 4/28/2009, THE LOW OIL PRESSURE SWITCH WAS REPLACED AND THE CONNECTOR INSPECTED. NO DEFECTS WERE NOTED, OPS AND LEAK CHECK GOOD.