sudo fine, sudo ls not working (command not found)

On Ubuntu 13.04 running in EC2, all commands through sudo work fine except ls. Here are some example commands to illustrate the issue:

ubuntu at host in ~
$ sudo ls
sudo: command: command not found

ubuntu at host in ~
 1 $ sudo which ls
/bin/ls

ubuntu at host in ~
$ sudo /bin/ls
bin  dotfiles  init  npm  tmp

ubuntu at host in ~
$ sudo pwd
/home/ubuntu

ubuntu at host in ~
$ sudo which pwd
/bin/pwd

ubuntu at host in ~
$ echo wtf
wtf

My dotfiles are here https://github.com/mike-spainhower/dotfiles

Line 40 of your .aliases is aliasing ls to a command called 'command'. Your system can't find this program named 'command'.

You can tell from your first sample error: the first instance of the word 'command' is the system naming the program it failed to find.