you might have better success if you create a macro in the other database that opens the form you want. Then in the OpenCurrentDatabase, pass the macro switch followed by the name of the macro.
Keep in mind that you probably won't be able to circumvent the other apps normal procedures. If it expects a login, you'll need to login. If it uses a switchboard to control operations, you'll need to open the switchboard.
What is the point of automating the form in a different app? You might be able to simply link to the BE and use a query to retrieve data if that is what you are trying to do. Forms are for human interaction. I don't recommend automating them via code. We may be able to offer a more specific solution once we know your actual objective.