I installed jPFChat, a phpFreeChat Component for Joomla. When I tried to run it, I received this error message:
LOCK_EX feature is not usable on your filesystem. Please do not use the 'file' container (try the 'mysql' container) or swith to another filesystem type.
I realized that the cause was because I am running my web site on an NFS partition.

I decided to try configuring jPFChat for MySQL.

Using MySQLAdmin, I created a MySQL database for jPFChat.

In this file: ./components/com_jpfchat/pfc/src/pfcglobalconfig.class.php

I changed container_type from "File" to "Mysql".

In this file: ./components/com_jpfchat/pfc/src/containers/mysql.class.php

I entered the hostname, database, username, and password for my MySQL database. I was required to enter this data at two different locations in the file.

Everything seems to be working fine!