Update:
There are various problems relating to Battle.net accounts, from the looks of it it's not just related to WoW Tunnels & Proxies. There have been many users reporting on the official World of Warcraft forums problems logging in.
If you haven't merged yet, I suggest to stay away (for now).
Possible fixes:
Open Freecap settings, go to the Program tab and change the DNS name resolving from "Remote" to "Local then Remote"
