Which user are you using to run ambari ?
If it is root then make sure that the directory "/var/run/ambari-server/" has root permission.
chmod -R 777 /var/run/ambari-server/
I see this is another issue now. Are you able to resolve the previous issue ? If so please accept best answer.
For current issue i will request to get a new post. Also if you can click on he failed task Eg. "Accumulo Client install" and post the logs that will be helpful.
Make sure you have access to download packages.
Make sure your firewall is off.