There have been multiple reports on the official Diablo 3 forums that trading a shield with a Templar follower encountered early in the game results in players being kicked out of the game and receiving a 3006 error message.
Players who have encountered this problem claim they are unable to log back into Battle.net. There have been suggestions that the issue may be tied to the Demon Hunter class.
Blizzard is aware of the issue and is looking into a fix for the bug. Until a fix is found, they advise players steer clear of the Templar.
A fix has been found by some players who did not want to wait for an official fix from Blizzard. The issue with the game appears to contained in a subfolder in the games ProgramData directories, making it inaccessible to the account for which the game was installed, including an administrator. Some Blizzard forum users have reported a fix for Error 315300 is to create a new Windows user account with administrator privileges, restart the computer, and load the game using the new account.
While this is inconvenient, it appears to be the best option until an official fix from Blizzard is released.
