After installation you get this message about - Font "Arial" does not support style "Regular".
This message tells you that you are missing that Font style. It's likely that it is corrupt or a windows update somehow removed it. That can happen when uninnstalling software
To fix this issue, please go to "Start", rightclick and choose "Run"
Then type c:\windows\fonts\arial.ttf
This dialog will appear and you click "Install"
When the installation is finsihed, please start your Revit with Naviate and the error message is now gone.