Which version of elgg are you using? Are you using any other theme?

Also, try asking on the plugin page

Rodolfo Hernandez
Arvixe/Elgg Community Liaison

I use 1.8.3 and use FB theme 1.4 (for 1.8.3). When i post in wall of my friend, i have error:

Fatal Error.

Redirect could not be issued due to headers already being sent. Halting execution for security. Search http://docs.elgg.org/ for more information.

Do you help me?

Try putting Custom Index plugin right after your theme.

I dunno if it works in yours. I have my own theme and have the same the problem, but it solved when I re-order Plugins by moving Custom Index at the bottom of all other plugins.

I encountered the same issue. Basically the theme is trying to redirect to dashboard on an index request. In order to fix this, I opened mod/facebook_theme/start.php and commented lines 381-383

// if (elgg_is_logged_in()) {
// forward('/dashboard');
// }