Unable to use Composer (for Drush) on Bluehost - install problem
Content-type:text-html means your script is running from CGI instead of CLI.

so try to fix your install so that the PHP in the path uses a CLI

One simple way to do is to write php path to php-cli instead of php-cgi.

# .bash_profile
export DRUSH_PHP=/ramdisk/php/54/bin/php54-cli