You are using illegal id-attributes(illegal before HTML5) inside the document, e.g. 2-slide . Fix them.
To explain:
to solve the known misbehaviour of element.querySelectorAll() the selector .slide will be internally rewritten(by using the id of the element). This will result in something like that:
#2-slide .moreselectors
…and forces the error, because an ID may not start with a Number.
See the fiddle: http://jsfiddle.net/doktormolle/FGWhk/