Was it maybe meant to be sent to another person with a similar username? I think when you go direct to the Inbox and initiate a PM from there you have to actually type in the username, you can't get the name just like clicking on the PM button from as post.

Edit - I just checked my Inbox and to send a new PM I have to type in the username without having any reference to look it up, unless the username is in my address book which is only my buddy list.

I looked at the userlist and there are lots of Chucks.