Ubuntu Installation :: Fetching From Servers Fail When Using Update Managers

I have Ubuntu Karmic 64-bit installed. Update manager tells me there are updates available, but when i try to install them, downloading the updates fail and throws this error:

Code:
Failed to fetch [URL]
Consequently, a similar error occurs when I try installing Sun Java 6 Runtime.

Code:
Failed to fetch [URL] Connection failed [IP: 91.189.88.31 80]
And of course Ubuntu Restricted Extras stalls when it's time to download the Java package

I tried synaptic, update manager, aptitude, apt-get, and they all throw similar errors. Then I also tried connecting to different servers, to no avail. So to check if it's my connection to the net that has problems somehow, I tried downloading the file directly through my web browser, and it works. (But it's not recommended, and it won't let me!, install the updates manually, right?) I then checked if I'm using some inappropriate proxy settings, and everywhere it's all set up to connect to the net directly, which is, well, my setup. Take note though, that I am able to install other software normally, i.e, using synaptic, apt-get etc. The ones I tried include Pidgin and Mplayer.

It's just these updates and Java:
Code:
jeanne@jeanne-desktop:~$ sudo sudo aptitude upgrade
W: The "upgrade" command is deprecated; use "safe-upgrade" instead.
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
The following packages will be upgraded:
libc-bin libc-dev-bin libc6 libc6-dev libc6-i386
5 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded .....

Code:
#
# sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com KEY
# Ubuntu supported packages .....