Website background length issues

Im working on a german homepage, covering the evolution of elevators.

Problem is the blue background on the 4 sites is not even. It suddenly stops and I want to go down from the top to the bottom on every site.

Im using Adobe Go Live 9.

Any ideas where to change this.

http://www.lift-lifte.de/

did u try adding to ur content div style
#content {
overflow:auto
}