Its a common problem with KLM that bookings do not show up properly on CMT.

Firstly it is important to be sure that the reference is the right one. Did it used to work? As far as I know a single flight change on a multi-flight itinerary does not change your booking reference, but it might depend on how radical your changes were.

You could try to login on klm.com->manage my booking. If that works the booking reference is at least still valid.

CMT currently has a problem with some KLM bookings, see this thread as well here:
http://www.flyertalk.com/forum/air-f...eckmytrip.html
If that is the case you should still be able to get the details using the mobile version of CMT, here: https://ideas.amadeus.com/tomcat/iph...formiphone.jsp

Best / most dependable way is to just use the KLM website. If you absolutely want more details, you could ask the KLM helpdesk to send you an Amadeus booking printout by email.