Can't import language file

I installed version 7.2.1 and I can't import my Dutch language file through admin panel.

I can select the file but when I try to open it, nothing happens.

File or directory permissions problem? If you uploaded it previously, and it was fine, maybe cleaning cache would help? Also import files have slightly different structure than language files. You should export first to compare. 

I know, I imported that language file before without any problem.

Installation of the script was ok, without error messages.

Permissions ok.

Cleared cache and even tried with other browsers.

No luck.

This is the reply of TMD hosting :

The experienced issue was caused by the the default Dolphin module "Files". While active, it literally translates the Dutch language file back to English. 

To make the language file work, we disabled the English language, removed the Files module and uploaded the language file again. Once the Dutch language file was working, we enabled English. Regrettably, any attempts to install the Files module again resulted in the language file being translated to English.

Given this, we have left the default language as Dutch and the Files module remained installed. Please verify if you would like us to keep the current configuration.

Has anyone imported another lang file on D7.2.1 yet without having this issue ?

Nobody having issues importing another language ?

I used the downloaded script 7.2.1 (not the 7.2 with the upgrade for 7.2.1)

I reported this as a bug.

The issue was due to mod_security rules which were set. TMD hosting has now edited this rules for my account and the issue is resolved.