There are some mistakes in my instructions:

/etc/bluetooth/rfcomm indeed needs to be /etc/bluetooth/rfcomm.conf

The ...nameserver... script should be called /etc/ppp/ip-up.d/dns, so /etc/ppp/ip-up.d/ should still be a directory. Note that there is an update later in the thread for PR1.1.

About the rfcomm bind problem - can you post the content of your rfcomm.conf file?