In the context of the PHP forum thread, what specific issues did the user face when trying to pass a variable from the layout page to the included guestbook page?

The user faced issues passing a variable from the layout page to the included guestbook page because the included page is treated as a separate file with its scope. To solve this, you can use the `include` or `require` function in PHP to include the guestbook page and pass the variable as a parameter in the function call.

// Layout page
$variable = "value";
include 'guestbook.php';

// Guestbook page
echo $variable;