PHP within HTML

I am running PHP 5.0 with an Apache 2.0 handler. One of these php files I am working on is being moved for the first time to an ISP that is also running PHP 5.0 and with a CGI/FASTCGI hander. problem 1: when the website's index.php displays, I get the message "<br /><b>Notice</b>: Undefined index: iuname in <b>F:\wwwroot\more file name \index.php</b> on line <b>255</b><br />". The line was written to display a Session variable. <input type="text" name="username" value="<? echo $_SESSION['iuname'] ?>" size="15" maxlength="45" tabindex="1" height="3">. Where can I look on the ISP server to ensure that php web pages can display values? Problem 2: (Might be related to problem 1 - so this may be a statement) I was given the ISP's php_info and compared it to my php_info. The ISP does not have APACHE running (no big deal I suppose) and does not have mysqli extension information in the php.ini (Is this a a reason why my code is not working). Help is appreciated. Jeff