Gnome 2.6 Main Menu modification
 

Hi all,
I type 'applications:///' in Nautilus in order to see the contents of my main menu but i'm not allowed to move or delete anything from them. I'm the owner of all but the default settings are 555.
When i try to 'chmod 755' i get the error:
"The permissions couldn't be changed - Couldn't change the permissions of "Accessories" because it is on a read-only disk"
Any ideas why this is happening? And is this URI 'applications:///' linked to somewhere on the filesystem hierarchy (e.g. /usr/share/...)?
That would help a bit cause i can't even find a way to get there through the console as root.
I haven't done anything in my profile and i've been looking for this thing for almost a month, but know that i finally found it, i can't use it...
I'll be waiting for your help.
Thanx in advance.