I am noticing some kind of error when using the Awards/DL-Skyteam Method, and the Airlines Quick option.

For example, KVS shows availability for flights IAH-AMS-MAD on 6/3/13 on KLM. I tried booking this in Delta.com 'by schedule', and I receive an error. I have contacted Delta and talked to two different agents, both of which confirm there is no such availability in the Delta system.

Any feedback as to why this search option reports availability that is not actually there? Am I doing something wrong?