understanding chkrootkit and rkhunter logs

Hi,
I'm sorry for asking a totally newbie question but I haven't found an answer to this. I'm really curious and concerned about what is reported by the chkrootkit and rkhunter on my Debian Etch home server.

Here's what I get when I run them:

CHKROOTKIT:

Searching for suspicious files and dirs, it may take a while... 
/usr/lib/xulrunner/.autoreg
/lib/init/rw/.ramfs

Checking `sniffer'... lo: not promisc and no packet sniffer sockets
eth0: PACKET SNIFFER(/sbin/dhclient[2181])

In the system mail I also get this:

/etc/cron.daily/chkrootkit:
The following suspicious files and directories were found:
/usr/lib/xulrunner/.autoreg
/lib/init/rw/.ramfs

eth0: PACKET SNIFFER(/sbin/dhclient[2136])

RKHUNTER reports this:

* Filesystem checks
   Checking /dev for suspicious files...                      [ OK ]
   Scanning for hidden files...                               [ Warning! ]
---------------
/etc/.pwd.lock /dev/.static
/dev/.udev
/dev/.initramfs
/dev/.initramfs-tools 
---------------
Please inspect:  /dev/.static (directory)  /dev/.udev (directory)  /dev/.initramfs (directory) 

Is this something to be worried about? How can I investigate further into these two issues?

Thanks,
Ale.