To modify the Enterprise Manager web.config
Element to be added :
<add key="DataTrackingConnectionString" value="[Connection string]" />
Add a valid connection string depending on your database that is used for data tracking.
Example:
<add key="DataTrackingConnectionString" value="server=[hostname];database=AgilePointTracking; trusted_connection=true" />
This file is located in the folder [AgilePoint Server installation]/Enterprise Manager