Writing to a File with PHP. Permissions?

[imroue]

When I try to write to a file I get this message:

Warning: fopen("gb.dat", "a") - Permission denied in x:\Web\OurSite\GuestBook\ardguest.php on line 567

This sounds like a simple fix with permissions. But I am not sure how to do this with IIS in Windows XP. Or is IIS the problem?
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after installing mailtraq

This is another message I get:
Warning: Failed to Receive in E:\Web\OurSite\guestbook\ardguest.php on line 583

Warning: Cannot add header information - headers already sent by (output started at E:\Web\OurSite\guestbook\ardguest.php:583) in E:\Web\OurSite\guestbook\ardguest.php on line 589

[Joan Garnet]

Go to your server vua ftp, select the file where the script is and then right click on it.
Change permissions to 777 which means that you give users full permissions (this is dangerous in some cases)

[imroue]

Go to your server vua ftp, select the file where the script is and then right click on it.
Change permissions to 777 which means that you give users full permissions (this is dangerous in some cases)

I use windows XP. Can't I do it within the file itself?
What settings are safe for the script to at least work.?

[Joan Garnet]

Yes, you can proceed the same way:
right click the file and go to security options, then select all permissions.
That's it