Hi guys
Thanks for the great plugin! I have installed a Joomla 1.5.26 and the All vid plugin (4.1). Works perfectly! Som of the .flv video files are quite large (1.5 Gb) and it still works OK. Though I have to wait for a good result until the buffer has loaded the entire moovie. But since it is on a LAN it's OK.
But with several concurrent connections the server comes to a halt even with smaller .flv  files (60Mb). and we are only talking 5 connections.

What could be causing this?

Probably it is related to your server settings...

On a side note, you may wish to consider migrating your site to Joomla 2.5