Lubuntu 12.04 won't do apt-get update

Question

I just finished installing Lubuntu 12.04. When I try to run apt-get update I get a whole lot of errors:

W:Failed to fetch [lists my repos] 
E:Some index files failed to download.

I tried with many, many different repos besides the official ones that come with the default out-of-the-box installation. Here's my /etc/resolv.conf file:

nameserver xxx.xxx.xxx.xxx
nameserver xxx.xxx.xxx.xxx
nameserver xxx.xxx.xxx.xxx
search la.xx.com

and my /etc/network/interfaces file:

auto eth0
iface eth0 inet dhcp
dns-nameservers xxx.xxx.xxx.xxx xxx.xxx.xxx.xxx xxx.xxx.xxx.xxx

(same nameservers as above) And this is the output of ifconfig:

eth0      Link encap:Ethernet  HWaddr 00:e0:52:bc:81:95
          inet addr:10.0.2.15  Bcast:10.0.2.255  Mask:255.255.255.0
          inet6 addr: fe80::2e0:52ff:febc:8195/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:26676 errors:0 dropped:0 overruns:0 frame:0
          TX packets:86212 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2246688 (2.1 MiB)  TX bytes:7211192 (6.8 MiB)
          Interrupt:11 Base address:0x1400

The weird this is, I have access to the Internet having configured Chromium with a socket to connect to. I am wondering if I still need (and where) to specify a proxy to do apt-get update. Look forward to reading your suggestions. Thanks in advance.