I need your support on Plugin translations...

Hello,
this time I really need help.
I have looked into it the whole day and I am stuck.
I have a french mulstisite install; when a new plugin is tranlated, the transltion comes in french automatically.
However I am trying to translate some plugins with poedit including your budypress activity plus.
I have bought poedit pro for this. Done everything i was supposed to do? but noot working.
The poedit dev is telling me it is coming from wordpress. I have checked a few itesm and cannot see what the issue could be.
Please have a look in my install and let me know what is the issue...
I have translated for exemple the plugin buddypress quick activity? the file po and mo are well in place, from what i would believe but nothing is happening.
Can you please tell me ... ?
Best regards,
Hervé