Issues writing to file in assembly

Question

I am trying to write a simple program in assembly in which I open an existing file and I write a message in it, a message which I define in my data segment. The problem occurs w

Answer 1

Alright, sorry for this question actually, but I finally figured it out. When I opened the file, I did

mov al, 0

which means I opened the file with read-only access. What I needed to do was

mov al, 1 (write-only access) or 
mov al, 2 (read+write access). 

Sorry for the bother guys, I'm just glad I finally figured it out.