How to fix "-5 No address associated with hostname error" while updating?
This has been a long term problem with apt, and Ubuntu has never fixed it. Apt doesn't seem to use the same DNS servers that the internal system does - 'ping ' returns a correct IP address. Apt-get claims that the hostname isn't found.
"Something wicked happened resolving 'extras.ubuntu.com:http" (Which sounds, somewhat, like it's trying to resolve a .com:http domain, which isn't a valid TLD)
To modify /etc/hosts, use the following:
Ping each of the names that are failing to resolve - PING extras.ubuntu.com (91.189.88.33) 56(84) bytes of data.
Use your favourite editor, such as vi - 'sudo vi /etc/hosts'.
Scroll down to the end, and add a line such as the following
91.189.88.33 extras.ubuntu.com (with the appropriate name and IP address. IP is first)
Save the file, then re-run apt-get. Once you've run apt-get, edit /etc/hosts again, and comment out the line with a hash mark - #. (or delete it entirely)
#91.189.88.33 extras.ubuntu.com
The reason to comment out/delete the line is that Ubuntu apparently shuffles their servers around randomly, and that might not be the correct IP the next time.
http://archive.scrapy.org/ seems like a perfectly working Ubuntu mirror, so while I'd usually ask you to provide information about what Software Sources are configured, it looks like this problem is either specific to your Ubuntu system, or was a short-lived problem with (or accessing) your DNS server. (The problem is not actually with the server at http://archive.scrapy.org/ itself, though it may have been due to a configuration problem for that server's DNS record.)
This is, of course, assuming that you have Internet access on the affected machine. If you don't, then you need to connect to the Internet before updating. It's quite normal to see errors like that if you don't have Internet access, or if your Internet connection itself is interrupted.
The problem may have gone away by itself. If not, you can try a different DNS server (8.8.8.8 and 8.8.4.4 are good public DNS servers operated by Google), and/or try a different mirror for updating Ubuntu.