I've recently install ubuntu 12.10 on a new drive mounted on /.
When sharing (via nautilus sharing options) directories from my home folder on the new drive it works just fine, and can access it from other computers with only the guest account(no password required)

But when I try to share folders in partitions from my older drives mounted in /media I get permission denied when I try to access these folders from another computer with the guest account. (the shares are shown but not accessible)

If I access these shares with my username it also works fine.
But It doesn't require my password! (if i remove guest ok and use my username it does require my password)

I guess for some reason for these mounts it treats my username as the "guest" username

Any ideas how I can fix it, so it will simply work with the guest account?