I am missing something, I guess... from where are you trying to access the DB, from outside the RaspBerry pi, or from within, as in running your app inside it?
You keep saying that from windows you can access and update the file from windows, and on your first post, you say you need to update it from a B4A app...
So you are trying to access a file from a different device than the one you are running your app from, right?
I think you have a permission issue when accessing from the B4A app (File access is something Google's has made way too complicated).
If you can't get access permission when working from Android, I would suggest you to create a middleware, running inside the Raspberry pi, to which the Android app can connect, and then the B4J app can execute the needed operations.