code problem

Hi,
I cannot do anything on my wordpress setup page…if i try to add or change the page is blank with the error message in the bottom “Read googleleads.g.doubleclick.net

Also
This is the line in the body –

Warning: Cannot modify header information – headers already sent by (output started at /home/hgruss59/public_html/wp-content/plugins/adsense-on-top/adsenseontop.php:78) in /home/hgruss59/public_html/wp-includes/pluggable.php on line 890

Thankyou