Extras bring errors

Everytime I try to activate or deactivate any of the plugins on the management page I get this error,

“Warning: Cannot modify header information – headers already sent by (output started at /home/glamynet/public_html/wp-content/plugins/comment-plugger.php:2) in /home/glamynet/public_html/wp-admin/plugins.php on line 22”

Line 15 when activating
Line 22 when deactivating

I didn’t change anything in the original plugins.php page.
This error comes up for the plugins installed for you too.

As for the plugins I installed myself they don’t work.

EDIT: It happens with themes too. A pattern to do with headers?