Avira Can’t Apply the Change of Configuration

Hi there,
I am the only user of my PC and I have all the administrator rights but I have this error when I want to change some settings in Avira. Can anyone tell me what could be the problem with my antivirus ? How can I get the permission to access the items ?
Thank you !

C:program filesaviraantivir desktopavconfig.exe
Windows cannot access the specified device, path or file. You may not have the appropriate permission to access the item.
