User Data Not Updating?

Hi,
I have installed the wordpress “User Registration” plugin and created a new field called ‘twitter’, where people can put in there twitter user-names when the register for an account so that I can have a link to people’s twitter account on the authors profile page. Now, this all worked fine until for a tutorial that I am writing I had to change the twitter username, and now it will not update. The correct value appears fine in the main user control panel, but it will not update on the profile page.

http://inspiredbywordpress.co.uk/author/danielgroves

Thanks in advance for any help,
Dan.