Yes, this is harmless 'bug' in kernel. It should be debug output and disabled. This is caused by power management which turns off the card when it is not accessed and then turn it back on. If you are bothered by this (because you regularly want to find something in kernel log :-) you may comment it out or use my custom kernel which has this line disabled.
see "N800/810 - IT2008 version 2.2007.50-2" section here http://fanoush.wz.cz/maemo/#pptp