I was also getting "Sending DHCP requests ...... timed out!" when using DM6467 Arago 2009.11 kernel. I added ":eth0" to the bootargs as suggested and now the ethernet comes up properly.
bootargs=console=ttyS0,115200n8 root=/dev/ram0 rw initrd=0x85000000,16M eth=00:0E:99:02:B5:A0 ip=192.168.2.101:192.168.2.6:192.168.2.6:255.255.255.0:DM6467:eth0::off mem=100M
