Jose,
Congratulations on your first Discussion Forum post, I think you will find these forums quite useful.
As for your question, after reading the description, I have found one possible solution in a KnowledgeBase. Here is the link to that KnowledgeBase:
LabVIEW FPGA Module Returns Compilation Errors When I Have Unconnected Outputs on FPGA Device I/O Fu...I would suggest reading that over and seeing if it applies to your situation. If that doesn't solve the problem, I would suggest that you post back with some additional details on your problem. Some of the things that would be helpful would be your version of LabVIEW, your version of NI-RIO, if you have been able to compile and download in the past, if you can compile and download a very simple program, and any other details that you think are important. With those details, this forum should be better equipped to help answer your question.
I wish you the best of luck with your application.
Regards,
Jed R.
Applications Engineer
National Instruments