iTunes update server could not be contacted

When I try to check for an update through iTunes it gives me an error that says: The iTunes update server could not be contacted. Please check your internet connection, or try again later.

I am running a Dell Dimension E520 with windows Vista 32 bit, 2GB of RAM. I have iTunes 7.3.2.6.

I have had this problem for sometime and have even uninstalled iTunes and reinstalled it, but it did not fix the problem. I would like to update to the latest version of iTunes, but have been unable to so far. Thanks for any help on this problem.