Giving writing permissions for IIS user at Windows 2003 Server

I am running a website over Windows 2003 Server and IIS6 and I am having problems to write or delete files in some temporary folder obtaining this kind of warmings:

Warning: unlink(C:\Inetpub\wwwroot\cakephp\app\tmp\cache\persistent\myapp_cake_core_cake_): Permission denied in C:\Inetpub\wwwroot\cakephp\lib\Cake\Cache\Engine\FileEngine.php on line 254

I went to the tmp directory and at the properties I gave the IIS User the following permissions:

• Read & Execute
• List folder Contents
• Read

And it still showing the same warnings.

When I am on the properties window, if I click on Advanced the IIS username appears twice.

One with Allow type and read & execute permissions and the other with Deny type and Special permissions.

My question is: Should I give this user not only the Read & Execute permissions but also this ones?:

• Create Attributes
• Create Files/ Write Data
• Create Folders/ Append Data
• Delete Subfolders and Files
• Delete

They are available to select if I Click on the edit button over the username.

Wouldn't I be opening a security hole if I do this? Otherwise, how can I do to read and delete the files my website uses?

Thanks.

Finally what I did was giving read/write/modify permissions on app\tmp folder for the Internet Guest Account.