I have the company's wordpress site under IIS 7.5 (Windows 2008R2 SP1) but I still have file access problems:
Under .NET Websites it's usual the IIS_IUSRS
the user used by IIS to perform tasks on behalf of the website user, but is it when using PHP as well?
As you can see I have set the correct permissions to the wp-content
folder and all of child folders (I did verify this).
What am I missing?
I think it has nothing to do with permissions.
Check this link, it might help.
Don't forget that IIS permissions are controlled through both IIS and NTFS. Make sure the directory is writable (the PUT verb) in IIS, as well as writable by the user that PHP is running under with NTFS. Both need to be working, or you'll continue to get that error.