@daysky The same thing happened again today. Request processed. I ended my turn. When I clicked the chat, I could see them saying that I left. (I was in the lead so they were curious). When I tried to reply in chat, I got a popup saying the match had ended. I have a screen shot but I don't know how to attach it here...
I played 3 to 4 games today and all of them either the game crashes or when I am about to win it bugs, and I cant build anything, cities/ settlements disappears. Also, people keeps quitting when they lose. Please fix these problems.
City wall helps you to store more resource cards on hand - read rules.
Only thing that stops barbarians except knights is citadel (level 4 upgrade of any kind) but that also protects just one city so if you have two out of which only one is citadel barbarians will invade other one if not protected.
About the screenshots: there is indeed no way to post screenshots directly into your message, but people have usually used a third party image hosting service such as http://imgur.com/ or http://tinypic.com/ where you can upload your screenshot in a few clicks, without creating an account, and then share the link on your message.
Regarding the inability to build a settlement because you get hte wrong type of object (such as a boat), you need to go to your board pieces, click on settlement, then click the checkmark. It will then allow you to place immediately.