Language problem

[bel303]

Updated from 3.4.8 to the last IPS4 version today, but we have a problem with language section, is not possible to add another language, it goes to blank page and doesnt work.

URL: www.domain.admin/?adsess=bh2rplfi0u91rofiv29t0uudi4&app=core&module=languages&controller=languages&do=form&id=2

 

Another way is duplicate the existing english default and upgrade it to other one, but after it is not possible to edit and change the name and flag (again blank page and doesnt work nothing).

 

Any suggest?