>I haven't used DBF tables in our .NET app, so this may or may not have anything to do with it ... but I'm wondering if your app is keeping the connections open? You should only be connected to your database as briefly as possible. IOW, open the connection, grab the data, close the connection and then do stuff with your data. When you're ready to update the database, open the connection, update the database, close the connection. Are you doing it this way?
The data adapter object goes out of scope on each request. So, this should not be a factor.