According to published reports, Jeppesen had actual knowledge of the consequences of its activities. A former Jeppesen employee informed The New Yorker magazine that, at an internal board meeting, a senior Jeppesen official stated, "We do all of the extraordinary rendition flights - you know, the torture flights. Let's face it, some of these flights end up that way." (Jane Mayer, The New Yorker, Oct. 30, 2006.)
If they did have explicit knowledge of supporting those actions, I can see how they could be held liable. My first reaction was that Jepp was being sued for providing chart services to the operators. If they were actively involved in the process, then they are liable. While I want no mercy for those who engage in terror, we are supposed to be the civilized ones. If we are going to bend the rules, we need to do a better job of keeping it quiet. Someone leaked the info that Jepp was involved, they can't be punished criminally b/c that would involved revealing details of the operations, so they get hosed this way. When it comes to spook stuff, keep your mouths shut.