import language does not work in 7.1.4

Hello.

I am running 7.1.4 version, new install.

In Languages Settings = Languages, the title "English", the code "en", the flag "gb" are set.

My /cache_public and /cache directories are empty.

Cache in admin settings panel is empty and is switched off.

I have deleted lang-en.php from directory /langs

In admin panel, language settings, when I try to import lang-en.php language file, I am given an error: Cannot create

yet, the file lang-en.php is created. However, its weight is only around 80 kb instead of 274 kb, which is the size of the default file from boonex. During the installation boonex did not fully uploaded the english language file, this is why I am trying to import the whole original file.

1) Can somebody identify what the problem may be and how to solve it?

2) Alternatively, I would be grateful if somebody could import the lang-en.php in my panel.

3) It seems that once the language file is created, the only way to add new key strings is through Add Key. However, you can only add one at a time. Is there a way to add a bulk of new key strings, for example through phpMyAdmin?

It does work; there is another thread in the forums on this.

There are topics on this subject, but none of them answer the question. Their main reply is to empty the cache. My cache is already empty.

All the modules are also uninstalled.

These are my steps. All cache is deleted everywhere.

1. I add lang_en.php and hit Import button.

2. Boonex starts loading and then gives an error _ADM_TXT_LANGS_CANNOT_CREATE

3. I click on Languages. English language is yet created. I click compile.

4. I check /langs directory. The file lang-en.php is there. However, it's 60-103 kb only, when the original file should be 274 kb. I can never get above 103 kb.

Can somebody help me import the original lang_en.php?

Any support from anybody?