error in mail log

We just installed a new web server under suse 9.1 with postfix and qpoppper. I watch my mail logs with "tail -f mail" in the mail line I always see: Aug 12 21:59:36 mail popper[10374]: I/O error flushing output to client crunruh at DOMAIN REMOVED [216.117.41.11]: Operation not permitted (1) [pop_send.c:689] Is this something to be concerned about? Thanks for the help. Neal http://www.susehelp