Google Webmaster Tools doesn't accept new Sitemap - What's the problem?

I'm currently using Google Webmaster Tools (see my post on Google Tools) for tasks like discovering queries that lead to my website, links to my site and submitting sitemaps to get better indexed by Google.

The thing is recently the last couple sitemaps i submitted are on a pending state without giving more information. I think this is wrong because in the past i clearly remember that when submitting a sitemap i got the message that i had submitted a certain number of pages, which was the same as in the test sitemap option(and got a date as well), but now the submitted pages number doesn't change.

The same sitemap submitted to Bing Webmaster Tools returns no problems and the right number of pages is submitted. Is there anyone out there having the same problem? Could it be that Google is making an update or something like that?