Error 404 if I use spanish.po

Hi,
I think I since last update of Calendar plugin don’t work well. I was using spanish .po, and after update, the tags are in english.

I have tried to upload the spanish traslation, but when put it on the folder, if I click to detail event shows a 404 page. On the page where is all events tags is showed in spanish, but in the detail it shows in english.

Any idea ?

https://wordpress.org/plugins/all-in-one-event-calendar/