Although not exactly a trap error, an Internal Processing Error (IPE) is associated with a SYS1915 error, which can be caused by the same conditions as a trap error and subsequently are solved in the same manner. The key to determining the type of error is in interpreting the error message. A message "The system has detected an internal processing error at location ##0160:FFF6FC01-000D:00015C01....." would tell you that you should follow the trouble shooting procedures for a trap 000D error. Locate the error message by finding the three zeros followed by a letter or number (...01-000D:00...). In the IPE message, it will generally fall after the first cluster of digits.