Pay attention to the filename you use for your heading and for the detail lines.
They are different from each other.
I would expect you would want to write the detail lines to the same file as the header line?
Also, though I have much less experience with the Android file system than the other Power Users, I suspect you are building your file path wrong. I usually see /DCIM/ higher up in a path.
I also wonder if that is even allowed, unless you do it right.
See FAQ Section: Files
P.S. The variables in your event block lack the adjective 'global' or any language translation of that word. Also, your use of item as a table row and as a list index is strange. Find a way to display your text before sending it into a File, so you can debug it.