On screenshot you gave you have 30+ players connected.
Also netgraph shows no bigger problems with lag, those smaller lags could be related to network not being able to push that many packets or server being to slow.
Also you haven't said if you are using maps clients have to download, this have big impact on network usually.
after speaking to my colleague who is helping he said there was around 20-25 bots on the server. plus me and him.
I have removed all the bots and got a couple of screen shots of what happens when he connects the server.
as for maps their is a odd few maps that are needed to be download from but the majority are the standard maps which are install on all machines.
before the dup connection is when the screen jumping starts.(in the file attached to the post)
This one is when the other player joined.
this is about a couple mins play (which you will already be able to tell
)
The photobucket images should reduce in time"