Important Jomsocial stop work when kunena is intalled

Hi how are everyone,
Like i said, when i finish to install kunena my jomsocial doesnt work, this error is came out:

The connection was reset







The connection to the server was reset while the page was loading.





The site could be temporarily unavailable or too busy. Try again in a few
moments.
If you are unable to load any pages, check your computer's network
connection.
If your computer or network is protected by a firewall or proxy, make sure
that Firefox is permitted to access the Web.


any sugestion?

It really would help if you read What information should I include when I ask for help (including how to post my configuration report)? so that we could understand what versions of Joomla, Kunena and JomSocial you are discussing. Thank you.

You might also search for "The connection to the server was reset while the page was loading" on this forum (and, generally-speaking, on Google ) for more information about such things.