The default format for Bazaar commit authors is "username <email@email.com>".
Cf. :

• http://doc.bazaar.canonical.com/bzr.2.0/en/mini-tutorial/index.html#introducing-yourself
• http://doc.bazaar.canonical.com/bzr.2.0/en/user-guide/configuring_bazaar.html#telling-bazaar-about-yourself
• http://doc.bazaar.canonical.com/bzr.2.0/en/user-guide/setting_up_email.html

So, when Hudson get changeset and extract author, it create a user :

• username : "username _email@email.com>" wich is not really usable for login ...
• name : "username <email@email.com>"
• email : "email@email.com"

BazaarPlugin or Hudson should better parse this type of author format to correctly extract username