Undefined erros in Studio to add fields.

I’m new to the community. I installed Suitecrm 7.8.4 (stable version), but I’m having problems with “undefined” messages and some errors that do not save changes made, specifically in Studio, to add fields.
I saw in the forum that this problem is due to permissions, but I already made several permissions oriented here in the forum, but nothing solved.
My last change was to give permission (recursively) all files and folders.

chmod -R 755.
chmod -R 775 cache custom modules themes data upload config_override.php

I also changed config.php to:

array (
‘dir_mode’ => 0755,
‘file_mode’ => 0775,
‘user’ => ‘’,
‘group’ => ‘’,

Can anybody help me?