Future Simple or Future Continuous

[crazyaboutenglish]

Hi, I'm confused when to use the future simple and the future continuous tenses. I have done an exercise and my teacher told me my answer was wrong:-

Question: "Do you want me to give James the File?"
My Answer: "No, it's ok I'll see him this afternoon so I can give it to him then."
My teachers answer: "No, it's ok I'll be seeing him this afternoon so I can give it to him then."

Can anyone please tell me why my answer is not correct and what's the difference between these two tenses?

Thanks!

[emsr2d2]

There is nothing wrong with your answer, other than there should be either a comma or a full stop after "it's OK" (and OK should be in upper case). There is no need to capitalise "file".
"I'll be seeing him later" is a little more colloquial and it's not necessarily a version I would teach students until they are at least upper intermediate. I would give "I'll see him later" or "I'm going to see him later".