problem with theme

I’m having a problem with a theme i created. when I change from my theme to another I get this error:
Warning: Cannot modify header information - headers already sent by (output started at C:\xampplite\htdocs\wp-content\themes\cleanly\functions.php:1) in C:\xampplite\htdocs\wp-includes\pluggable.php on line 329

here is my code in that file:

<?php
if(function_exists('register_sidebar'));
register_sidebar(array('name'=>'sidebar1'));
register_sidebar(array('name'=>'sidebar2'));
?>

I have been over it with a fine…

I had tried to uplad this them to the theme viewer, but it wouldn’t work on there, thats when i found this bug… I’m not sure why this is happening and if it’s why it will not work on the themeviewer or not…