Display Name asked at every sign in
 

For the last week, 11/15/09, Windows Messenger v 5.1.0715 has been asking the
following every time it starts up.
"Please provide a display name so you can sign in. Do not use your e-mail
address or leave the box blank. We now require a display name that is not
your e-mail address to protect you from e-mail virus attacks."

My display name is saved in tools/options and has been for years. It is not
my email address! Why now must I type it every time I sign in? I am running
Windows XP Pro with SP3 and every update.