Operation not permitted

[rollingblackout]

greetings,

just upgrade to 4.0.3 and got lot of this in the logfile

/usr/sbin/popper[19536]: I/O error flushing output to client
user_login_name at 
a.b.c.d [a.b.c.d]: Operation not permitted (1)

can some1 shed some light on this?

regards,