Wow... something tells me this is going to be a long night... your site also doesn't pass the NATS code:
http://secure.jelenajensen.com/track/MTI3OjQ6MQ/
becomes:
http://www.jelenajensen.com/index1.html?nats=
The cookie is placed correctly by the NATS software though and I can only hope that I am the ccbill_referrer *107
I am hoping because my decoded NATS code = 127:4