>When I use #Include there does not seem to be an error if the file is not found
>
>for example if I put #INCLUDE c:\acats\xxxxaaaa.h and that file does not exist, I still do not get an error.
>
>How do you know if a #INCLUDE file loaded?
>
>Should I see an error if it does not load or does not even exist?

Yes, you should get a 'file does not exist' error when the program is compiled.