i have used the $_SESSION[] array to set a variable, but i cannot get that in a page when i visit the page for the first time.when i visit it second time i get the values.Please help me to sort out the issue.

Perhaps you could place a bit of your code down?
if you put:
<?php
session_start();
print $_SESSION['animal'];
$_SESSION['animal']="Zebra";
?>
then officialy you're not going to see it before you refresh the form .. ??!

I have had same problem. There was two PHP seperate sites I was using session in. However one of them was working; other was always not. Actually it even was not giving errors or warnings. In fact, I had to unuse sessions. I looked at bugs list. There was something related to this. I think it was because, I called "session_start()" from an include file.

I could not solved problem yet. If anyone who knows sth. about this problem, could help?

This problem may be easily solved:
In php.ini, session.use_trans_sid is usually disabled; hence u've2pass SID in url to other Web pages, session_start() should be called at the top of Web page code, and session variables should be declared, befrore u echo/c them.