MD5Sum Mismatch!?!

[Luis Murillo]

I want to install Alexandria, but this is what I get:
--
lmurillo at gir:~$ sudo apt-get install alexandria
Reading package lists... Done
Building dependency tree... Done
The following extra packages will be installed:
  libamazon-ruby libart2-ruby libatk1-ruby libgconf2-ruby
libgdk-pixbuf2-ruby
  libgettext-ruby1.8 libglade2-ruby libglib2-ruby libgnome2-ruby
  libgnomecanvas2-ruby libgtk2-ruby libiconv-ruby1.8 libpango1-ruby
  librexml-ruby1.8 libruby1.8 libyaml-ruby1.8 ruby ruby1.8
Suggested packages:
  ruby1.8-examples
Recommended packages:
  libgettext-ruby-util libdbm-ruby1.8
The following NEW packages will be installed:
  alexandria libamazon-ruby libart2-ruby libatk1-ruby libgconf2-ruby
  libgdk-pixbuf2-ruby libgettext-ruby1.8 libglade2-ruby libglib2-ruby
  libgnome2-ruby libgnomecanvas2-ruby libgtk2-ruby libiconv-ruby1.8
  libpango1-ruby librexml-ruby1.8 libruby1.8 libyaml-ruby1.8 ruby
ruby1.8
0 upgraded, 19 newly installed, 0 to remove and 3 not upgraded.
Need to get 159kB/2603kB of archives.
After unpacking 10.4MB of additional disk space will be used.
Do you want to continue [Y/n]?
Get:1 http://us.archive.ubuntu.com hoary/universe libyaml-ruby1.8 1.8.1
+1.8.2pre4-1 [159kB]
Fetched 159kB in 14s (10.6kB/s)
Failed to fetch
http://us.archive.ubuntu.com/ubuntu/pool/universe/r/ruby1.8/libyaml-ruby1.8_1.8.1+1.8.2pre4-1_i386.deb  MD5Sum mismatch
E: Unable to fetch some archives, maybe run apt-get update or try with
--fix-missing?
--

Could someone please fix this, please :)

-- 
Luis Murillo M.
lmurillo at gmx.net
Heredia, Costa Rica