Installation locked
This installation has been blocked to prevent two people executing the installer at the same time.
If you are the administrator and therefore the person who really will make the installation, you must erase the lock file: tmp/instalar.lock (for PHPFileNavigator versions earlier than 2.3.0) and in data/servidor/tmp/instalar.lock for 2.3.0 or later versions.
Once you have erased the lock file you must quickly update the page to unlock the the installer, and thus to obtain the permissions necessary to continue.
To clarify any confusion about this process or the use of PHPfileNavigator, please first visit the official page http://pfn.sourceforge.net/ and you will be able to find solutions to your problems in the forums.
Lito.