This message box displays when PM Compass attempts to load changes into the Schedule Change log and an error occurs. One reason an error might occur is when the log contains a change to an activity that has been deleted from the live schedule.
Check the system log (OPWIN.log) for more details about the error and the Schedule Change log to see the changes that PM Compass was attempting to apply. You can access the system log from within Open Plan by clicking Open Log in the Log Viewer menu group on the Tools tab.