Installation problems with Fuerte and rosjava

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Hello everyone, I'm trying to install rosjava for use with fuerte on Ubuntu 12.04 I followed the installation instructions substituting fuerte for electric. Everything seems to be working fine until I run the rosws update command. I'm rather new to linux so I'm not sure what I should be doing to fix this. Any help would be appreciated.

~/ros_workspace$ rosws update   
[rosjava_core] Installing https://code.google.com/p/rosjava (default) to /home/docsmiley/ros_workspace/rosjava_core
WARNING [vcstools] Command failed: 'hg --version'
 errcode: 127:
/bin/sh: 1: hg: not found
[/vcstools]
Exception caught during install: Error processing 'rosjava_core' : Unable to create vcs client of type hg for /home/docsmiley/ros_workspace/rosjava_core: "Could not determine whether hg is installed 'hg --version returned 127, maybe hg is not installed'"

ERROR: Error processing 'rosjava_core' : Unable to create vcs client of type hg for /home/docsmiley/ros_workspace/rosjava_core: "Could not determine whether hg is installed 'hg --version returned 127, maybe hg is not installed'"