Trust Center - Trusted Locations are greyed out
 

Microsoft office excel security notices pop up is displayed when I start
Excel 2007 to either "enable macros" or "disable macros"

I enabled the 3 of them

I go to "Excel Options" -- "Trust Center" -- "Trust Center Settings"

The "Trusted Locations", "add new location", "remove" and "modify" are
greyed out

Trusted Locations was okay two weeks ago when I updated to 2007 and added
the location paths to my startup files with macros embedded in them.

Where do I change the policy for this restriction?