TDN and Display Names...

I have successful visited TDN when I bought TGE last week. I then changed my display name to "BLiTZWiNG" and when I clicked the login link, I got "Your Display Name Is Already In Use!". I tried making up random strings, including "-BLiTZWiNG-", "T-BLiTZWiNG-T", "TDN_stop_being_picky" and "Trent "BLiTZWiNG" Tait".

Every time it's the same error.

Changing back to my orignal display name "Trent Tait" lets me in. So, while I can get in, I can't unless I use my original name. Is it me or the system?