x box and streaming problem

[#1]

Hi
I have a Belkin router which services the following networked boxes
192.168.2.2 Desktop XP Home
192.168.2.3 Roku Soundbridge
192.168.2.4 XBox 360
192.168.2.5 laptop xp home
192.168.2.6 ipod touch
192.168.2.7 Desktop
All IP addresses are assigned by the router. At its most extreme you might have a wireless blackberry and a wii  on the list too making a total of 8 devices.
The problem comes between the 1st desktop which runs firefly media server to the roku soundbridge. most of the time this works fine but from timetime time the connection goes and the music stream is interupted. The signal between the desktop and the router and the soundbridge and the router seems strong enough and noiseis tolerable.
I'm now stumped as to what to try next.
My only clue lies in the fact that the problem often  arises when my sons turns off his x-box. while both are running all is ok but once the x-box goes so does the soundbridge.
I thought about  giving the x-box and the desktops static ip addresses outside the pooling address ranges. I also thought it might be a problem with ports, both of these are a little beyond my experience ( willing to learn).
Any help or ideas please....

[#2]

Hi there groundsman,
                                      You got quite a lot going on there with that belkin,i hope its a good one!!XBOX 360 only uses one ot two ports and if you need to know which ones just ask me i know what they are,could be your router is getting very confused,i hear belkins are not the smartest?

[#3]

Thanks for the advice. I've thought about replacing the Belkin for awhile but it never really seemed absolutely necessary and without clear evidence that it is at fault I didnt want to go down that road.
I've been playing with this problem for over a week now and have come to the conclusion the Xbox is not the problem. ( why would it as all the evidence poits to a wireless problem
The more likely problem I think is the new Panasonic digital phones I got recently. I think these might be interferring wiht the signal between the soundbridge and the router. Iv'e tried changing channels 1, 6, and 11 but the problem persists on all of them. I also turned off turbo mode ( whatever that is) and WMM as this is supposed to behave better in noisy environments.
The laptop and the desktop seem to hold the connection OK but streaming will be more problematic I assume.
So after all that it still rubbish and not working relaibly. A router reset and fresh connection seems to cure it for a few hours but that is too tedious to do all the time.