[ubuntu-nz] Upgrading from 6.10 to 7.04

[Bob Harvey]

Hi all,

Just to introduce myself, I have been in IT for ever (well, decades) though the longer I'm doing this stuff the less I seem to know.  Lately I have been trying to upskill myself on Linux enough to dispense with Windows (as far as possible, anyway).  I tasted Suse but found it too tricky, and have ended up with Ubuntu.  Version 6.04 has worked fine on my laptop (with the exception of the Winmodem, of course) and I recently decided to upgrade to 7.04.

This has to be done via 6.10, for which I had the CD, so away we go and after a couple of hiccups managed to get there.  By this time the 7.04 CD had arrived, so I stuffed it in the slot and it didn't want to know (i.e. a file listing comes up but no Upgrade prompt).  After a lot of stuffing around (mostly through my own ignorance and impatience, of course) I have got stuck.  I should mention that I'm on diallup, though I can use a friend's 'broadband' connection by arrangement.

First, the web upgrade page says you have to have your 6.10 right up to date before going to 7.04.  When I run Update Manager > Check, I get an error:
   Could not download all repository indexes.
   The repository might be no longer available or could not be contacted because of network problems. 
   If available an older version of the failed index will be used. Otherwise the repository will be ignored. 
   Check your network connection and the correct writing of the repository address in the preferences.
   http://archive.ubuntu.com/ubuntu/dists/edgy-security/main/source/Sources.gz: Sub-process gzip returned an error code (1)

I have no problem manually downloading the Sources.gz file, so I suppose this is not the problem.  The setting of repository preferences for Update Manager seems to have changed from that documented in the Update Manager Manual.  This shows a Preferences button, which lets you set repository preferences.  This seems to be no longer available, so I have not been able to find out how to set update repository preferences for the Update Manager.

Second, if I assume I am up-to-date and hit the 'Upgrade to 7.04' button, it cannot find the same file 'Sources.gz' and closes.  Further experimentation with Update Manager can produce the following error:
   An error occurred.
   The following details are provided:
   W: Duplicate sources.list entry http://security.ubuntu.com edgy-security/universe Packages 
        (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_edgy-security_universe_binary-i386_Packages)

I cannot see any duplicate entries in /etc/apt/sources.list The relevant lines are:
   deb http://security.ubuntu.com/ubuntu edgy-security main restricted
   deb-src http://security.ubuntu.com/ubuntu edgy-security restricted main multiverse universe #Added by software-properties
   deb http://security.ubuntu.com/ubuntu edgy-security universe

I have since been told that the standard release CD for 7.04 cannot be used for upgrading (pity this is not clear on the web site) and you have to use the 'Alternate CD' which is not shown amongst the CDs available for ordering, but seemingly has to be downloaded, a non-trivial exercise even on a high speed line.  I have read through the instructions for a manual upgrade but am not confident of my ability to get this right.

Meantime strange things are happening -- program startup (e.g. getting from login to the desktop, or starting Firefox once there) is taking a VERY long time, maybe 2-3 minutes or more.  So I really want to get to a clean system.

So, I am baffled as to:
1)   Whether my system is in a fit state to upgrade to 7.04.
2)   If not, how to discover what the problem is and fix it.

Cheers all and blessings to anyone who can help,
Bob.