Install ubuntu12.04.2 with preseed file, but there is one buggy problem about preseed mirror setting.

The symptom here is installing process got stuck.

So I track down the log file, and find out the real problem, the installation is looking for a file that's not there.

This is just one of them, another pops up if I faked this file.

This all happened during preseed, so I believe preseed has something to do with this.

I google ubuntu preseed mirror and find this post saying:

# If you select ftp, the mirror/country string does not need to be set.
#d-i mirror/protocol string ftp
d-i mirror/country string manual
d-i mirror/http/hostname string archive.ubuntu.com
d-i mirror/http/directory string /ubuntu
d-i mirror/http/proxy string

# Alternatively: by default, the installer uses CC.archive.ubuntu.com where
# CC is the ISO-3166-2 code for the selected country. You can preseed this
# so that it does so without asking.
#d-i mirror/http/mirror select CC.archive.ubuntu.com

# Suite to install.
#d-i mirror/suite string lucid
# Suite to use for loading installer components (optional).
#d-i mirror/udeb/suite string lucid
# Components to use for loading installer components (optional).
#d-i mirror/udeb/components multiselect main, restricted

I wonder the difference between d-i mirror/http/hostname and d-i mirror/http/mirror, I mean they all specify a mirror, right?

In my preseed file, this is no d-i mirror/http/mirror, and d-i mirror/http/hostname points to my own repo as you might notice in the previous image.

Here is my question:

1. Does preseed fetches file/resource from internet, if I use local repo?
2. Why it's looking for file that's not even there?

This has bothered for quite time, many thanks in advance to anyone who might give any help.