Error: [ lang count (3) and file count (4) don't match or file count is 0 ]

[elblogdemac]

I am trying to add one more language to the web page following the tutorial to add a language, but when I add a new language I get this error in the section where I can change the interface language on the web page:
[ lang count (3) and file count (4) don't match or file count is 0 ].
If more information about the error is required I will give it.

[MrGreensWorkshop]

Hi, Please watch these videos, if you still don't get it, check this commit.