I have had the same error. I used Azureus before without problems but now I got the same error as you mention. I have found a solution that worked for me
The thing is that I have changed my local IP address and didn't think that it could have any impact on Azureus... but it did. So my solution was the following:
0) got my local IP address by running "IPCONFIG" form within a command prompt
1) from within Azureus went to "Tools | Options"
2) selected "Mode"
3) changed the mode setting to "Advanced"
4) selected "Advanced Network Settings"
5) noticed that the "Bind to local IP address or interface" was set to my old IP address (you should consider to stop this steps if that is not the case for you)
6) changed the "Bind to local IP address or interface" to my new local IP address
7) restarted Azureus
Well, this is very detailed so ANYBODY should be able to follow it.
Btw, remember to change your "Mode" setting if you don't want it to be "Advanced"
Hope it helps others