I constantly experience the same problem on my n800.
In my case I can successfully update the list as follows:

1) After it fails the first time. I go to 'Menu>Tools>Application manager>Tools>log'
... and click on 'Clear'. When I then refresh the package list again. it updates without a hitch .

OR

2) Just running the update process twice in a row also works for me.

I know this solution sounds too simple, judging by the log you posted, but why not give it a try

If that does not solve it, you could try the workaround stated at the end of your log:
'You may want to run apt-get update to correct these problems'

I am not familiar with all of the 'apt-get' command options.

If you don't have it, you can get maemo hackers Xterm, to run apt-get, here:
http://maemo-hackers.org/wiki/OssoXterm

I wish you luck solving your problem!