This isn't a REGISTER problem, but an end-user problem.  He
exceeded the LISTSERV threshold of bogus/incorrect commands
to LISTSERV.
 
As nice as REGISTER is, it is not necessary to do so in
order to use LISTSERV facilities.
 
As your post indicated, the user's privileges to issue
commands were suspended UNTIL anybody else issues the
LISTSERV command (to the IRISH site):
 
SERVE userid@node
 
/Pete Weiss -- Penn State