Thumbnails on Two Lines?

Hi!
We are currently using Slideshow Gallery on our test site, and it’s great so far! One small problem though, there appear to be 2 rows of thumbnails, rather than one. The very last thumbnail is underneath/ below the first one thumbnail, and the slideshow isn’t automatically showing that particular image. I have tried inserting less thumbnail images, but that doesn’t seem to solve the problem. I would really appreciate any help with this one. Thank you!
Gerri
http://nurseryculture.com/portfolio/girl-rooms/celebrity-nursery-in-los-angeles-residence/

http://ww.wp.xz.cn/extend/plugins/slideshow-gallery/