Buffering while streaming

[#1]

I have a rather anoying problem, I normally upload a stream to web site for the community using adobe flash media streamer and providing no body else in the house wants to watch any streaming video, all is well. Yet as soon as a member of the household want to watch anything, like BBC I-player the downloaded video is unwatchable as it is almost continually being buffered, any ideas what is wrong?
Bye the way my router is synched up with the exchange at full speed 8128Kb down and 448Kb up, can you have two streams running together, one up and one down?
Any thoughts?

[#2]

If you are maxing out your upload bandwidth when sending your data then there will be delays in receiving video (and other files). This is because as part of the download process, your browser has to send back frequent small packets of data to acknowledge the data received so far - the sending server can only send so much data without it being acknowledged by the receiver. If those packets are delayed in getting back to the server streaming the data the data feed will stop until the replies are received.
Also your router may not be quite up to the job when maxing out upload or download.

[#3]

Peter
Thank you for your reply, I was thinking it was the lack of upload capability was the limiting factor, data with overheads and bye the way the router is a 18 month old Belkin model.
Is there any tweaking I can do to improve matters, other than suspending the streaming being set to the data house when another member of the family wants to watch anything.

[#4]

This might be a bit of a long shot, but does your router have any "QoS priority" (Quality of Service) settings that you can use to distinguish between streamed and non-streamed traffic ?
Therefore you could prioritize whatever it is you are streaming, and then everything else can use the remaining bandwidth.
This sort of feature can be vastly different between routers, and obviously becomes more flexible with the more expensive models.
But it is probably worth a look, because if it can be made to work then it won't cost you anything (unless you end up buying a superior router).
If your router does not support adequate "QoS", then it might be worth investigating if there are any third part firmware downloads that do.