Louis just got back from a cruise and he has a ton of videos. But when he backed up his images and videos to his computer, the videos didn't sync from his iPad. Leo says that the issue is that Windows PCs handle media over Wi-Fi differently.
The Chatroom says that Picasa may not be able to see the folder. He should also try syncing each video manually, since it requires so much bandwidth. He could also sync with a wire instead of Wi-Fi, as that should certainly work. Apple has a tech note on this issue at support.apple.com. There's also an article at imore.com that suggests a fix.