XPath parsing gives me an error
===

I'm trying to get the first image from [this][1] site but I keep getting an error and can't quite figure out why..

Here's the code:

    string pictureurl = webdoc.DocumentNode.SelectSingleNode("//div[2]/table[1]/tr/td/a").Attributes["href"].Value;

and the error is `Object reference not set to an instance of an object.`

Can anyone please tell me why? if I remove the above line it works fine..

  [1]: http://leagueoflegends.wikia.com/wiki/Akali