To remedy this, from the Practice Partner server click on Start - Control Panel - Administrative tools - Services.  Scroll down to the "PMSI Application Service."  Right click on "PMSI Application Service" and select "Restart."  If the service stops but doesn't restart, right click on the "PMSI Formulary Service" and select "Stop."  Wait for at least 2 minutes then right click on the "PMSI Application Service" and select "Start."