SharePoint Server 2010 - Site administration

I have recently installed SharePoint Server 2010 in out environment. I have designated myself as an Administrator (also Farm admin). I have created a new Site successfully, but when I try to do the following :

a. Share this site

b. Change site theme

c. Set a site ICON

d. Customize the Quick Launch

I am getting the error below:

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What file is missing ? I did not encounter errors during installation and setup.

Regards,

Nelson