[X4U] Network locations question

[Paul]

Hi everyone.

It's been a while since I posted to this list, probably a few years.  
I found much help here when I started using OS X, but as time went  
by, I found I could fend for myself on most issues. But now I have a  
new iBook G4 1.42 GHz 14" and I am not only using new corners of the  
OS that I hadn't before,  but I'm also learning about an entirely new  
set of technology: WiFi.

My first question concerns my at-home local network and the Network  
System Prefs pane.

I have a cable modem coming into an ethernet hub, which fans out to  
the eMac downstairs and two cables in my room upstairs (desk + bed)  
for the iBook. The eMac is set up with Brickhouse so as to share the  
internet connection with my iBook. This is because I am using the  
same interface to share the connection on the eMac, and OS X's built- 
in internet sharing option has DHCP enabled, no matter what, possibly  
creating a problem for the rest of my cable network. Better safe than  
sorry.

At university, I have a static IP assigned, along with a valid  
hostname. I have a Location for the uni and a Location for my home  
setup.

The problem is that I am not allowed to set my iBook's name in the  
Sharing pane as I want it: kasumi.local instead of kasumi-2.local,  
which I am forced to do, since the prefs pane tells me that there is  
another computer using the name kasumi.local on the network. What  
might I be missing here? The eMac is obviously not called kasumi.

Thanks in advance.

Paul