I have exactly the same problem as in this thread. I am running latest Joomla and have PHP Safe Mode off. All my folder permissions seem fine 0777 and 0666. Any ideas what I may be missing?

Warning: file /var/www/vhosts/xxxx.com/httpdocs/xxxxx.com/administrator/components/com_comprofiler/pluginsfiles.tgz still exists. This is probably due to the fact that first installation step did not complete, or second installation step did not take place. If you are sure that first step has been performed, you need to execute second installation step before using CB. You can do this now by clicking here: please click here to continue next and last installation step.

When I click for the last step, I get this message:

Error while opening {/var/www/vhosts/xxxxxx.com/httpdocs/xxxxx.com/tmp/install_4e6921858cb92/index.html} in write binary mode
Installer - Error
Uncompressing /var/www/vhosts/xxxxx.com/httpdocs/xxxx.com/administrator/components/com_comprofiler/pluginsfiles.tgz failed.
[ Continue ... ]

When I hit continue, I am returned to a comprofiler page with the original error message.