OpenCart Community

I am using a Opencart 2.1.0.2 (new installation) and using a default Extension installer in this version.

I purchased many modules from opencart but all of them don't work and give the error...

"501 Method not Implemented" Get to admin/index.php is not supported.
Additionally a 404 Not Found, error was encountered while trying to use an Error Document to handle the request.

Error log showing this...

2016-06-04 13:03:50 - MOD: Modification Default
FILE: system/engine/action.php
REGEX: ~(require|include)(_once)?\(([^)]+)~
LINE: 39
FILE: system/engine/loader.php
REGEX: ~(require|include)(_once)?\(([^)]+)~
LINE: 20
LINE: 59
LINE: 80
LINE: 99
FILE: system/library/config.php
REGEX: ~(require|include)(_once)?\(([^)]+)~
LINE: 23
FILE: system/library/language.php
REGEX: ~(require|include)(_once)?\(([^)]+)~
LINE: 25
LINE: 31

Pls. suggest

It is not errors log - it's ocmod log
See Tools-Error log and your server's log

I am having a similar problem and cannot get an answer. Been troubleshooting for days, it even is happening in brand new fresh installs of multiple versions (tried 2.0 and 2.2 so far). No information at all in the Error log.