This doesn't work on my Mac either. MyDrive Connect doesn't even see my Via 53. There's no option to "Manage community content". The web addresses above don't lead anywhere either. Got to say, I only just bought this SatNav but it'll be going back to the shop tomorrow if I can't find at least a workaround.
Just Google "Name of POI" + POI
or Google "Free poi files"
I use this site the POI are free but you have to join the site