The problem is that your account doesn't have privileges to access that folder. To change these settings and give your account full access do the following:
1. Navigate to C:\windows
2. Right click on installer folder and select properties
3. Click on security tab.
Make sure the everyone group has read and execute, list folder contents, and read set to allow. The system group has all selected to allow except special permissions. The administrators group has all selected to allow except special permissions.
That should fix it!