I had a problem like this many times. When instruction is timetabled author has to insert two diferent kind of messages: 1) for instruction completed successfully (like "Good job, you completed on time and sucessfully the scenario."); 2) for failed instruction (like "You arrived late at final destination, try again!").
If author forgets the message for "failed instruction" you guess you went fine, but in fact you didn't! Most of time only the last instruction (usually at final destination) is timetabled. When playing the scenario check if that instruction is timetabled (second mini clock from left to right) and if you arrived on time.
When author forgets the "failed" message, scenario seems to finish successfuly, but you can confirm on the report screen if you have completed all destinations (5 in 6 means you failed, despite of no especific message saying you failed).
That's the most commom reason, maybe exist many others...
Hope this helps. What scenario is? I can look into...
Who doesn't have dog, hunts with cat.
