Shared Library in iTunes they disappear

Ok crew, I am about at my wits end on this one...

Here is the long of the short of it....

When I click on a Shared Library in iTunes they disappear.

Here is what I am dealing with:

1 Mac 10.6.4 Computer a
1 PC Win7 Computer b
1 Mac 10.6.4 Computer c

All are running iTunes 9.2.1. All are logged in to home sharing with the same UID and PW. Just an Ethernet switch between them. No firewalls, etc.

Computer A - the main host (the one i am really trying to get to.)
I open Itunes and turn on home sharing. There is a 'done' button on the bottom right. Under shared I see:

a dark brown house: Home Sharing
a light brown house: Computer B
a light brown house: Computer C

I press the done button. The dark brown house disappears and I am left with:

a light brown house: Computer B
a light brown house: Computer C

I press the light brown house: Computer C, and it disappears! (Mac)
I press the light brown house: Computer B, and I have access (W7)

Ok. So i go to sit at Computer B (Win7). I see under shared:

a light brown house: Computer A (mac)
a light brown house: Computer C (mac)

I press the light brown house: Computer A, and I have access.

So, I go sit in front of computer C. I see under shared:

a light brown house: Computer A (mac)

I press computer A, and the icon changes in to some blue note thingy.

I press computer A again, and it disappears.

Now, here is the real kick in the pants.

I log off account '1' on computer C, and log on to an administrator account on Computer C.

I see:

computer A -but it is the blue note thing, not a light brown house

And.... it works. Of course :0

So, if you are still with me (thank you), I am really trying to access computer A (mac) from computer C (mac). It works using and admin account, but not a 'typical' user account.

Thoughts and ideas would be greatly appreciated. Thank you.

Update?

Ok,

So I opened wireshark on computer B, the Win7 box. And, when i click under shared in itunes on Computer C (mac), I see a complete handshake. All's good.

I open wireshark on Computer A (Mac). And when i click on Computer C, the only thing I get is an MDNS server flush. That's it.

And, when I click on Computer B from Computer C I see the full handshake. (aslo get the server flush.)

So what gives? Computer C shows up in the Shared List, but Computer A makes no attempt whatsoever to contact it?