|Such things may happen when including header files in the wrong order, required header files has not been loaded, or are skipped due to exclusions. Because we don't know the other headers file that might be involved, it can't be answered for now.
A common problem is the inclusion of winsock2.h. This must be included before windows.h. I mention it here beacuse RPC is network related.
If this does not help you should try to find out the correct order by inspecting the header file inclusion tree. You can generate an include file tree by editing your project settings (Configuration Properties - C/C++ - Advanced - Show Includes).
Inspect the line of error (154 in rpcnhdr.h) to know which definitions trigger the error. Then try to find these definitions in header files included before that.