Adding an additional IP or IPs to your network card in Linux is easy. Here’s how I did it in my Fedora Core 4 installation:
cd /etc/sysconfig/network-scripts/
cp ifcfg-eth0 ifcfg-eth0:0
Now you will need to open your newly created ifcfg-eth0:0 file in your favorite editor and modify it to fit your needs. The two lines you MUST change are the following, the rest are optional:
DEVICE=eth0:0
IPADDR=192.x.x.x
Of course you will want to fill in the IPADDR value to fit your needs.

Now, to make the changes take effect, you will need to bring your new IP up by issuing the following command:
./ifup eth0:0
Or if you want you can just restart the entire network:
/etc/rc.d/init.d/network reload
There you go! Run ifconfig and you should see your new IP assigned to eth0:0. It should look something like this:
eth0:0 Link encap:Ethernet HWaddr 00:D0:B7:B7:XX:XX
inet addr:192.168.1.XX Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
You can add even more IPs by repeating this process and incrementing the value of eth0:0, for example you can add eth0:1, eth0:2, etc.

I was receiving the following error after completing the setup for Retrospect Express HD with my Maxtor OneTouch External Hard Drive:
Can't save setup, check the selected drive to make sure there is enough free space.
I had plenty of space on the drive, so I knew this couldn’t be accurate. After some research I found out that my config file was corrupt and it was an easy fix: Remove or rename the RestorePoint.rbc file in the Retrospect Restore Points folder on your external drive. Open up Retrospect Express HD and it will re-create a new config file, as well as re-create all your restore points. This can take a very long time (hours) but once it’s done you’ll be back up and running like new.

(Source: http://forums.dantz.com/)