A good place to start would be to test the connection between the two machines…
Were you running that other non-stock stuff before you networked the two machines together? The system mount you made should have close to zero impact on the system and although a slow connection to a MySQL server will impact some of the menus it should not have much in the file manager. If your not going to actually use the shared database you could just remove the advancedsettings.xml and go back to using a local database if that is the issue.