TimThumb Permissions Issue

Website: http://stitireandwheel.com
WordPress version 3.1.2
Yamidoo version 1.6 theme

I’m building a new site and none of my images are appearing, on the home page or in my posts. This theme uses TimThumb. I have scoured the theme’s support forum, documentation and video tutorials. I thought it was a permissions issue, as outlined in the theme’s support info, and stressed repeatedly in this WordPress forum. I tried changing the specified directory permissions via FTP and found that they would not change. I’d make the change to 755, click OK to exit that dialog box, and then discovered that they’d revert back to 644. No error message that I could see. At that point I contacted my host for assistance.

The following is information this host asked me to forward to the theme provider (WPZoom):

Subject: Yamidoo Theme – Permissions on Windows 2003 IIS Server
Message: I have a Windows 2003 Server running WordPress. A developer installed a Theme WPZOOM called Yamidoo and it is not displaying the thumbnail images. We believe it is due to the permission on 2 folders…..wp-content\themes\yamidoo\scripts and cache folders. Currently if I FTP to those folders the permissions show 644 and your documentation says they need to be set to 755 or greater.
– I need to know what to change on my Windows Server to make the equivalent of that happen.
– Currently the IIS_IUSRS account has everything but Full control.
– The IIS_IWAM account has All Permissions including Full Control.
– The owner of the folders are IIS_IUSRS.
– I drilled down thru IIS to the Scripts folder and set IIS properties on that folder and the Cache folder to include WRITE.
– The Execute permissions (in IIS) on those folders are set to Scripts Only.
– I also tried setting the IIS Execute Permissions to Scripts and Executables on these 2 folders.
– I am running PHP 5.2.6

Your Help would be much appreciated.