If you receive an error related to "Base table fields have changed" after installing SP 4 for Dynamics GP please perform the following steps:

Here are the steps to reset the database container files in Messenger Server.
From the File menu select System Configuration.
Choose the Database tab.
From the Accounting System Version drop list select 6.0
Click the save button on the upper left
Click No when prompted to restart the Server
Go back to File | System Configuration | Database tab
Reselect 10.0 from the Accounting System Version drop list.
Click the save button on the upper left.
Click Yes when prompted to restart