Problem connecting to server through iTunes for ios update

I have an iPod 2. I must update the ios using iTunes because my ios is 4.3. How do I solve the problem when I am trying to update the ios from iTunes but I continually get the message in iTunes, "The software server can not be contacted. Check your network connection?" For all other purposes my network connection is fine.

I did finally update the ios using another computer. At first I received the same mmessage. Then it worked and I updated the ios. Now I must resync the iPad with the original computer but it will not recognize the new ios because iTunes is an old version. When I attempt to update iTunes I receive a similar but different message, "The iTunes update server could not be contacted. Please check your Internet connection, or try again later." I receive this message each time I attempt to update iTunes. Again, my Internet connection is fine and works for all other purposes. I am presently running ITunes 10. Any help would be greatly appreciated. Thanks