Indeed according to EU regulation has an exception (to which company always refer to) that is that no compensation is due if the cause of delay/cancellation have been extraordinary circumstances (i.e. event beyond the control of the airline that could not have been reasonably prevented).

However, several EU rulings state that tech failures are not of this kind. Despite this, airlines constatly try to get away not paying the due compensation, and force you to ask and ask (and sometimes go to court).

A neat explanation, together with some relevant court cases, is actually on wikipedia
http://en.wikipedia.org/wiki/Regulation_261/2004

I agree with the previous poster in that you are IMO entitled to compensation, and I advise to pursue this further with KLM (and if needed with the national enforcing body). There are also companies that can take care of the lagal aspects for you for a fraction of the amount litigated (if compensation is awarded).