Hi Rimi,
While searching for a possible solution to your question, I came across a Knowledgebase entry on our web site. Its ID is 251BSUKN. Although PCI-6023 is not specififcally included there, taking a look at it might provide you some good insight into the problem. Also in this knowledge base, you will find an attachment of the kdf files. Please do take a look at the tutorial under the related links too. To access the knowledgebase, go to ni.com/support and type this knowledgebase ID in the search box at the bottom of the page.
I hope this helps.
Sincerely,
Sastry Vadlamani
Applications Engineer
National Instruments