The problem was that Paypal change the normal response values that the system use to get and handle the payments, the system was not getting the expected values and you can imagine that the system just shouts down the whole process and kill the execution if something looks strange.
Anyway, is "fixed" now. I will keep an eye on this issue so if you notice the same error please keep in mind that all the orders are processed in no more than 12 hours in the worse scenario.
Hope you can understand.