You should read up on FolderItem.
It sounds like your db is located in the same folder as the application. If so, then just declaring a new, empty FolderItem will give you the current path to it, like so:
Var f As New FolderItem("")
MessageBox "Current folder = " + f.NativePath
I would recommend you try to create a FolderItem directly for the db, to ensure it exists where you think it is. Something like
Var dbFile As New FolderItem("db1.mdb") //assumes db is in same folder as application
If Not dbFile.Exists Then
MessageBox "Database not found!"
End If
But as Dave suggests, you shouldn’t put the database in the application folder. It should go in a “user data” folder, either Documents (SpecialFolder.Documents) or the OS specific place for application data (SpecialFolder.ApplicationData as Dave suggests, but you should create a subfolder for your app).
Now, if the database is meant to be a read-only, reference type database, then you could put it in the application’s Resources folder (SpecialFolder.Resouces), and include the file in a Build Step so it is copied into the Resources folder when you run or build.