If you are not able to see servers with the in game server browser please try the following:
Press the Stop Refresh button, then uncheck show map list. Be sure you are on the Internet tab of the browser and hit refresh now.
If this doesn't work, try the steam server browser out of the game as detailed below.
Exit out of the game, right click on your steam icon in the system tray, choose servers, change filters to "Pirates, Vikings, and Knights II" and click refresh all.
You should now be able to see servers, join one. Then see if you can see servers in the ingame server browser.
Unchecking "Show map list" in the in game server browser will give a text only list of servers which some find easier for looking through a large number of servers.