Warning: Failed to move file!

saluteveterans,
SSH is basically a 'command line' where you can type different commands you want to perform. I know nothing about Cloudserver though, and wouldn't know how to help you. Basically, you'll need to make sure the permissions for your files and directories are correct. You can easily do this from SSH by following the post below:
www.corephp.com/blog/fixing-permissions-on-your-joomla-site/

With luck, that will fix you up. If not, you may need to make sure the files are 'owned' by the right user. This is completely server dependent, so you'd need to check with Rackspace as to what user should own the files for a PHP website. Hopefully, you won't need to do this though and the above post will help get you started.

Best of luck to you,
Alex