Wow, I'd like to give a five-star to AVChat for their efforts to do their best to answer all of my questions.
For not being a programmer, it was a daunting task to set up a media server, install a plugin and AVChat program.
It was much more complicated than installing a plugin.
Yes, hosting a video chat wasn't a easy task at all especially because I could hardly understand what is going on and what to do next to make it work.
However, AVChat support team provided me such a wonderful, instant support (often responding with right answers in less than a hour), I was able to make it running in my VPS.
I think you can count on them. I highly recommend them.