Accelerator pedal cuts out as rpm builds

[tree98]

Well, not having much luck here. My 7.6.2 is saying it can't connect to my ecm, I suspect that this engine is to new and not compatible with my version of insite. Its giving me an error 5204. Also tried it on my X15 and it won't connect to it either, says it's not supported. I know some of you said insite 7.6.2 won't work with the x15, but a lot of guys also said it works fine. Am I doing something wrong?