The suggests there are still spaces at the end of lines 1,2, 7 and 12. Or that the changes you have made are not uploading to the server.
The headers already sent errors occur because of output to the page between PHP code blocks.
In the error, it reports the output is at line 2:
output started at /misc/39/000/158/672/0/user/web/africanregister.info/Admin/admin_LogOut.php:2
In the page you originally sent, there where spaces at the end of lines 1 and 2 causing the error:
"<?php require_once( "../WA_Globals/WA_Globals.php" ); ?> "
"<?php require_once( "../WA_SecurityAssist/Helper_PHP.php" ); ?> "
If those spaces ave been removed, make sure the changes are being uploaded to the server.
Try deleting the logout page from the server, then uploading it again.