I had this version FreiChatX 6.3.2 and it was working fine and I would like to upgrade to the FreiChat.v.7.2.zip. After I've uploaded and extracted the file, then I've visited the link http://www.mydomain.com/freichat/
This is the message that I'm getting

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, webmaster@mydomain.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

What Am I doing wrong? how can I upgrade My chat?
Anticipating Thanks

I've change all files and folders' permissions (/freichat) to 755 and it worked like a charm
Thank you guys.
you can also view the post from the admin
http://evnix.com/drupal2/node/681#comment-2298