Failed to install

Hello,

I'd like to install cmssh on my laptop. I'm following the instruction from https://twiki.cern.ch/twiki/bin/view/CMSPublic/WorkBookCmsshTutorial, but I get following error when running the installation program:

$ python cmssh_install.py --install --dir=$PWD
Checking CMSSW
Bootstrap CMSSW
Init CMSSW apt repository
Find latest CMSSW release
Find /bin/sh: 1: source: not found release deps
/bin/sh: 1: source: not found
Traceback (most recent call last):
File "cmssh_install.py", line 1265, in
main()
File "cmssh_install.py", line 595, in main
name = find_cms_package(apt_init, cmspkg, debug, lookup, rel_pkgs)
File "cmssh_install.py", line 214, in find_cms_package
name = natsorted(vers)[-1]
IndexError: list index out of range

Could you help me with this issue?

Philippe.