The error means it can't connect to the patch server for whatever reason. Assuming you're having the somewhat common problem of connecting to a bad server, you have to...
Search the start menu for notepad, right click it and run it as an administrator. Open:
C:\Windows\System32\drivers\etc\hosts
At the bottom, at the following line, then save:
52.206.178.33 assetcdn.101.arenanetworks.com
Now start the launcher. Remove the line once you're done, since the IP will eventually change and cause this problem.
(normally you'd do this by using the -assetsrv option, but it's been broken for months)