What is the difference between the one in the Site configuration section and the one currently in the Labs section?
A Google Webmaster Help thread has a response from Google's JohnMu on the key differences. He said:
The general Sitemaps section gives you information on whether or not we could download and parse your Sitemap file. This is a technical requirement before we can even analyze whether or not the content of the file is usable in our indexing pipeline.
In the Video Sitemaps Laps feature, we analyze the content that you have submitted as a Video Sitemap, and give you feedback on any issues that we have found while attempting to index the videos that you specified. So I would recommend first making sure that your files are parsable (in the Sitemaps module) and then double-checking to see if they're useful for video search (in the Video Sitemaps section). If you've updated your robots.txt file in the meantime, you can double-check some of the URLs mentioned there by using the Fetch as Googlebot function, which will only fetch the URL if it's allowed.
Here is a video from Google on video sitemaps:
Forum discussion at Google Webmaster Help.