I experienced that problem, too, but suddenly it worked - and I really
do not know why!

I have got a ~5 year old computer with slow network connection running ubuntu 
lucid 10.04.1 (was upgraded from 10.04 via alternate CD)
When trying to upgrade to 10.10 with the alternate CD, I also received the 
error 'E:Error, pkgProblemResolver::Resolve generated breaks, this may be 
caused by held packages.'

Going through apt.log I found a lot of messages "Try to Re-Instate ...", most 
of them for xserver-xorg-video-... packages.
I had all possible xorg-video drivers installed (via xserver-xorg-video-all) 
and decided to remove all except -nv (which is the one I have enabled in 
Xorg.conf) and -vesa (for fallback).
Result: still the same error, but with a lower number of "Try to Re-Instate 
..." messages in apt-log.

Next try: digging through program sources to find out who writes those messages 
-> seems apt
Checking release notes of apt shows that from 0.7.x (lucid) to 0.8.x (maverick) 
the messages in algorithms.cc have been extended to show more information in 
the pkgProblemResolver steps. Thought it could be a good idea to update to the 
latest (maverick) release and try again, hopefully receiving more indications.
Downloaded apt_0.8.3ubuntu7_i386.deb and installed with package manager 
(message: "all dependencies satisfied"), but alas, this broke almost all apt 
and synaptic packages because apt 0.8 is no longer providing 
libapt-pkg-libc6.10-6-4.8 but libapt-pkg4.10 (still have to check if I should 
report a bug about that).
apt-get install -f wanted to remove lots of packages (which I refused)
So back, installed apt_0.7.25.3ubuntu9.3_i386.deb via dpkg.
Happy to see that apt-get install -f did not show any problems any more.

Next try: could my system be upgraded to 10.10 via network download?
started update-manager to upgrade via network -> and it was able to resolve the 
dependencies and asked me if it should really start the upgrade. (estimated 
download time 7 hours for files that I already have on CD, so I decided to 
abort). apt.log did not show any "Try to Re-Instate ..." lines.

Synaptic told me that there are half a dozen new erlang... packages
available, so I installed these updates.

Next try: back to the alternate cd, with the idea to enable debug messages as 
much as possible. Created an apt.conf with several  Debug::xxx "true".
What can I tell: sudo sh /media/Ubuntu 10.10/cdromupgrade worked!
Now apparently it was able to resolve the dependencies and asked me if it 
should really start the upgrade. (decided to cancel because it was already late 
in the evening, and I wanted to keep the possibility to try to chase this bug 
further).
Again apt.log did not show any "Try to Re-Instate ..." lines.

Tried again without Debug enabled, and it worked again -> so seems not
caused by debug enabled.


What I do not know now is which step in my attempts is the one that is 
responsible that it works now (up-/downgrading apt, installing erlang..., 
trying to upgrade over the network once, ...).

What I suspect is that the appearence of  "Try to Re-Instate ..." lines in 
apt.log leads to the 'E:Error, pkgProblemResolver::Resolve generated breaks, 
this may be caused by held packages.' message. All apt.log files of failed 
upgrades in launchpad bugs that I looked at have those. Maybe mvo can shed some 
light on that?
What I also could think of is that the number of dependencies and conflicts to 
resolve at my first attempts was too high, and reducing the number of 
dependencies/conflicts (by removing xorg-video-... and upgrading erlang...) was 
the key.

Sorry for the lengthy post, but I thought I should add all the information that 
possibly could help to find the cause of the bug (and maybe a solution).
I am willing to do some more tries on my system.

regards, MH

-- 
Failed to upgrade to 10.10 with alternate ISO - E:Error, 
pkgProblemResolver::Resolve generated breaks
https://bugs.launchpad.net/bugs/658581
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