Someone else (Kevin) found the solution on this website: [url]http://anantgarg.com/2009/05/13/gmail-facebook-style-jquery-chat/[/url]

Chat now works flawlessly so far for me. Basically change the lines below in chat.php :

$dbh = mysql_connect(DBPATH,DBUSER,DBPASS);
mysql_selectdb(DBNAME,$dbh);

to

@$dbh = mysql_connect(DBPATH,DBUSER,DBPASS);
@mysql_selectdb(DBNAME,$dbh);

Kevin says that ... "My MySQL was outputting some additional information which can be disregarded with the “@” symbol, therefor the json actually passes the correct username to the script.

Hope it helps!"

Thank Kevin, not me, :)