Setting file permissions

Hi, I am trying to set up a PHP page that writes to an XML file. I am getting this error:

Warning: fopen(writeArticlesHere.xml) [function.fopen]: failed to open stream: Permission denied in C:\Inetpub\wwwroot\writeArticle.php

How do I set IIS permissions so that files in the folder can edit other files?

I am running windows media center (just an extension of xp pro) and this is just a local server. I am running IIS 5.1.

Thanks for your help.
David

It's not other files that edit other files, you need to allow the user account that IIS is using to write files. Typically this is the IUSR_computername user account, just use windows to grant that account write permissions to the desired folder(s).