mitydsp@mitydsp-dev:~$ sudo apt-get install nfs-kernel-server
[sudo] password for mitydsp: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be upgraded:
  nfs-kernel-server
1 upgraded, 0 newly installed, 0 to remove and 273 not upgraded.
Need to get 159kB of archives.
After this operation, 0B of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
  nfs-kernel-server
Install these packages without verification [y/N]? y
Err http://us.archive.ubuntu.com/ubuntu/ lucid-updates/main nfs-kernel-server 1:1.2.0-4ubuntu4.2
  404  Not Found [IP: 91.189.91.23 80]
Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/n/nfs-utils/nfs-kernel-server_1.2.0-4ubuntu4.2_i386.deb  404  Not Found [IP: 91.189.91.23 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
mitydsp@mitydsp-dev:~$