Control Panel failing to save value

Hello, the control panel is failing to save a value upon a permission error.

I'm attempting to change the setting to allow special characters within the title.  (Why, by default, commas, periods, and dashes are considered special characters and stripped out of the title is another thread entry in itself.  I guess Sitefinity doesn't like to encourage grammar.)  According to this thread:

www.sitefinity.com/.../special-characters-in-pages-titles-in-q1

I need to strip out the values within RegularExpressionFilter.  However, when I do so, and then save, I get error:

Access to the path 'C:\clients\drbowyer\SiteFinity.New\SiteFinity\App_Data\Sitefinity\Configuration\ContentViewConfig.contentViewControls.FrontendPages.views.FrontendPagesCreate.config' is denied

I am logged in with full privs under Admin.  I'm sure you appreciate my frustration.  It shouldn't take this much work just to put a period into my page title.

Hello,

It looks like the file is either locked by another process or you have not granted permissions to Network Service to access and modify the Configurations folder. It needs permissions to change the configuration files.