It is tough to tell what you have done wrong since you have omitted the most important thing - how the field is defined in your RPG or how you populated it. What i can tell you is that the value you see equates to spaces - so I would guess that the field is defined in an unititialized DS and is never being populated.
Just to be sure I created a file with just an 8 byte Int like so:
So what you are seeing are blanks in the space where you are expecting the field to be. Either you're failing to read the record, or you've done something unusual in the way you've defined things in RPG.
Like Jon said, it's difficult to help you since you have omitted the most important things that we'll need to know to answer your question.