http://www.photonics.com/content/news/2007/April/4/87089.aspx

Here are some quotes
"What the analysis shows so far is that something extraordinarily simple was missed in the design. We do many very complex engineering projects successfully that require sophisticated engineering skills and advanced computing tools. We test the complex features we design thoroughly. In this case we are dumbfounded that we missed some very simple balance of forces."
""Not only was it missed in the engineering design but also in the four engineering reviews carried out between 1998 and 2002 before launching the construction of the magnets."