since you are developing the software to work with CAN driver for EG20T, I would high recommend you to go through the PCH EG20T CAN Driver windows Programmer Guide
Go through your code to see if you made any mistakes and etc. if you are really confident withe the your application, I would also suggest you try the same test on windwos 7 embdded. we provide the driver package in EDC too. see if you are getting the same issue ? it might help with you and us to narrow down the root cause.
In the last I would suggest you or get your hardware engineers to check the hardware is properly deisgned, it must met Intel's recomendations in our EG20T Platfrom design guide the CAN bus section. But since CAN is only a low speed signal, so there is really few possibily that some thing went wrong in the layout.
So good luck with your trouble shooting and feel free to reply with any questions or status update.