Well i contacted Marine Traffic today, they have done some changes, so if you have problem using the site, you must uncheck Adblock or other programs like this, on the page, this is why the map will not show up, i also sit in Norway "Skien" and using Mac, but the problem is known by them at both Windows and Mac machines.
They will not change this, because their policy is, you need to pay, if you want to get rid of the ads, so looking for other sites to watch traffic now " I really hate ads "
Brgds Torben