A Google Webmaster Help thread has several webmasters complaining that the fetch as GoogleBot feature is not working.
I should note it works fine for me, but several webmasters are saying that when they run it, it returns a red X and says "failure."
John Mueller from Google responded to the thread saying:
We're looking into this and should have some feedback for you guys soon. Thanks for your patience.
This does not seem to be an issue with every site but only a select number. How large that number is, is the big question.
So just a heads up that if the fetch as GoogleBot tool doesn't work for you, you are not alone.
Forum discussion at Google Webmaster Help.

Comments:
Josh Closser
11/24/2011 01:20 am
Good Evening (at this time) :) I have made a post, seeing this has been a rising issue lately, If you use google analyticator this fix will work for you. I have written a post on how to fix the problem, you can read here: http://www.joshclosser.com/2011/11/23/fetch-googlebot-failed-fix-2031180.jsp Short URL: http://goo.gl/unrru
Matthew Shuey
08/09/2012 04:23 am
Google Fetch seems to be intermittent. Googlebot seems to crawl just fine.
Josh Closser
08/17/2012 06:28 pm
Yeah, the sop i made back then was wrong on some of the settings, I didn't get around to fixing the settings to a t. *However I did notice, that it seems to bug out when you try fetching a 2nd option before the first fetch-page-reload completes. eg: fetch website, fetch as phone, fetch as chtml - clicking fetch again before the previous has finished created bugs for me. I have waited for the page load to complete since then :)