SAP Note 21598 - PA-TRV: simulation of travel accounting incorrect

Symptom:

The simulation of a travel expense accounting run terminates, and the following error message is issued:
56 018 Simulation of trip & is incorrect.

Cause and prerequisites

Some table entries needed to carry out accounting for this trip are missing.

Solution
In the Travel Expenses menu under Process -> Accounting, start the accounting program (RPRTEC00) for the personnel number and trip number in question.
The 'Accounting log' parameter should set as 'ON' (Release 2.1, 2.2.)
or
the accounting parameter 'Test run with log' should be selected (as of Release 3.0).
This detailed accounting log records the point at which the accounting run had to be terminated and also shows the table entries that could not be found.