Problem with session var scoping -- please help

[lostarts]

My session variables are disappearing and I can't figure out why. Any pointers appreciated. Here's the (simplified) code:

In INDEX.PHP:

<?php
include ("set_env.php"); // has session_start()

$_SESSION['foo'] = 'bar';

'<frameset cols="150," rows="" border="1" frameborder="1" framespacing="0">';
echo ' <frame src="frmMain.php" name="osamain" frameborder="0" />';

echo '</frameset>';

?>

In FRMMAIN.PHP:

<?php
echo "foo=".$_SESSION['foo'];
?>

The output is:
foo=

isset($_SESSION['foo']) returns false. Why isn't this session variable passing to the scope of FRMMAIN.PHP?

Thanks for any thoughts,

Jeff

[lostarts]

Here's what I was doing wrong.

FRMMAIN.PHP should've looked like this:

<?php
session_start();
echo "foo=".$_SESSION['foo'];
?>