Reading through similar issues on the forums, I assume this is the known issue with the transfer/faction change, where the character inadvertantly gets flagged for rename when it isn't necessary.
To clarify, it isn't as much of a "known issue" as it is a limitation in how the system currently works.
Basically, if you transfer a character and the name is already taken on the destination realm, your character will be flagged for a rename. When you log into the character you'll be prompted to select a new name that isn't currently in use.
In many cases where a faction change is done in addition to a transfer those using the service often change their character's name through that service, giving them a name that should otherwise be unused.
Unfortunately, this method of renaming does not remove the flagging that was placed on the character in the first place. In these cases the flag must be removed manually by a Game Master (by submitting a petition or support site ticket) or by selecting an entirely new name.
You should be set and able to log in once more. I closed the ticket you opened to avoid any complications. Thank you for opening the ticket, though Support Forum Agents like myself try to help when we can, we aren't always able to get to each and every post. :)