This means that NameNode is not started of not bound to your IP address.
Could you check if port 8020 listed in “netstat -a” output?
If it listed, make sure it is bound to your IP, no to “localhost”.
Also, what mount points you defined during the installation? make sure that is is NOT /dev/mapper/xxx.
Take a look at hmc.log, find which command is failed.
Use sticky note in http://hortonworks.com/community/forums/topic/hmc-installation-support-help-us-help-you/
run mentioned script and send results.