Error while installing COMSOL on amazon AMI

I was trying to run COMSOL on amazon. While file following the link "http://ift.tt/1akTD3X", I face errors when trying to install COMSOL on the AMI. When I try to install COMSOL into the remote terminal: " cd ~/Private/comsol/COMSOL43b_dvd/setup ami", i get this error: "bash: cd: /root/Private/comsol/COMSOL43b_dvd/setup: No such file or directory"