I've not seen any errors from that yet, but I do note several things:
 
Name convention similar to Stu's.
Site in the U.K.
User signed up to a large number of lists in a very short time.
Bouncing mail from user.
Last name (Nuthall vs. Wrathall)
 
I  don't think this is a coincidence - I think we have a very malicious
user out there, and need to do something about it pronto!
 
 
Paul Goodwin
IBM System Support
Georgia Institute of Technology