Need Help With A wordpress error

I am having an issue with a wordpress warning when I login into the dashboard for 1 of my sites. It says:

Warning: Cannot modify header information - headers already sent by (output started at wp-content/themes/IMSC Heathmap Pro 4 Lite/functions.php:2262) in /home/myusername/public_html/mywebsite.com/wp-includes/functions.php on line 861

Warning: Cannot modify header information - headers already sent by (output started at /home/myusername/public_html/mysite.com/wp-content/themes/IMSC Heathmap Pro 4 Lite/functions.php:2262) in /home/myusername/public_html/mysite.com/wp-includes/functions.php on line 862


Does anyone have any idea what this means and how to fix it?

Thanks In Advance

not 100% but

try placing this at the top of your page:
<? ob_start(); ?>

then at the bottom of the page place this line of code:

<? ob_flush(); ?>

It is with the theme IMSC Heatmap lite or something installed on your website....change the theme and the error will go away...if u want to keep the theme..let me know and I will try to find out a solution