500 Internal Server Error after create a ftp account to access document root

Good night, after performing maintenance changed the permissions of the htdocs folder, I can not return to normal, you could help me?

tail -f /usr/local/apache/logs/error_log

[Mon Jul 25 21:18:06 2016] [error] [client 127.0.0.1] SoftException in Application.cpp:249: File "/usr/local/apache/htdocs/index.php" is writeable by group
[Mon Jul 25 21:18:06 2016] [error] [client 127.0.0.1] Premature end of script headers: index.php

I have been to fix the cwp and not solved.

try using fix account permissions for "nobody" user in CWP.admin

I already tried to do this but not solved
the commands are performed below

sudo chgrp -R apache /var/www/html

sudo chmod -R g+w /var/www/html
sudo chmod g+s /var/www/html

after the command worked perfectly for an hour, then he stopped and began the Internal Server Error problems