Before anything else, get the latest patches for your respective game version. Also, check out Sierra's help page for solutions for known issues.
Depending on your progress, at the beginning of day five Grace may give you the Rada Drum Book twice, and when the phone rings Gabriel says he'll get it but he never moves. This can be fixed the following ways:
Before you start day 5:
Depending on the speed of your computer, it might be impossible to get into Mosley's office on day 6 because the solution is timer based and the distraction might not last long enough to reach the office. To progress, you can use either of the following options:
Note that you do not need to reload if the beignet guy already left the station and you failed to get into the office. In that case, apply either fix and return to the police station, the officer will fall asleep after some time permitting you to get into the office.