RTNETLINK answers: No such process
There is already a pid file /var/run/dhclient.eth0.pid with pid 5126
killed old client process, removed PID file
Internet Systems Consortium DHCP Client V3.0.4
Copyright 2004-2006 Internet Systems Consortium.
All rights reserved.
For info, please visit http://www.isc.org/sw/dhcp/

wifi0: unknown hardware address type 801
wifi0: unknown hardware address type 801
Listening on LPF/eth0/00:08:02:e2:d9:6b
Sending on   LPF/eth0/00:08:02:e2:d9:6b
Sending on   Socket/fallback
mom@MUSICLAPTOP:~$ sudo ifup eth0
There is already a pid file /var/run/dhclient.eth0.pid with pid 134993416
Internet Systems Consortium DHCP Client V3.0.4
Copyright 2004-2006 Internet Systems Consortium.
All rights reserved.
For info, please visit http://www.isc.org/sw/dhcp/

wifi0: unknown hardware address type 801
wifi0: unknown hardware address type 801
Listening on LPF/eth0/00:08:02:e2:d9:6b
Sending on   LPF/eth0/00:08:02:e2:d9:6b
Sending on   Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 13
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 7
No DHCPOFFERS received.
No working leases in persistent database - sleeping.