"Do you thinnk I am missing a header file for it. The program compiles fine."

If 'fine' means 'without errors or warnings' and you have the warning level set to maximum then I doubt you're missing a header.

"I looked at the header files and the only one I found containing this volatile word is <absacc.h>. I included it, but still does not work."

'volatile' is a 'C' keyword. Look it up in your 'C' book.

Your original post is a code fragment, not a program. Create the smallest program you can that exhibits the problem and post it with HTML formatting tags. Someone should be able to spot your problem.