Hi there!
[FONT=Comic Sans MS]Welcome to the forums Elahe!
Allow over-writing in the case of my plugin node determines whether or not I will delete a file if it already exists and update it with new contents.
It is a safety precaution to avoid overwriting existing files, and so if you want to keep updating a file, you should definitely allow over-writing!
The only reason to turn off would be to protect a file from being changed at , not updated, which is what you want, so just leave over-writing enabled and you will be set!
Have fun today!