some media servers automatically create some folders, like pictures, videos. did you run the computer as administrator? according to the error, you need to login the computer as administrator

did you reboot the router? if there is not internet at all, hard reset the router. if you don't want to reset, disconnect the router from your modem first, connect only one pc to the router to login....

What's the model number of your print server?

If the device has something wrong and under the warranty, they will help you to replace it.

Means new web interface page.

Can you send the screenshot of DSL section on Advanced--Status page? When you lose the internet, what's the status of the LED lights on the modem? How often does the issue happen?