Mp3 Patch on Cubase 5 Ai

I have a Cubase 7.5 in my studio and a 5Ai to be used in travel time. I’m out of my city and I need to make some simple adjustments on a track using my laptop with 5Ai on.
I’ve bought the patch to export in mp3, installed it but on my MacAir it still doesn’t work.
Relaunched both Mac and eLicenser but nothing, in Cubase I got always the “The license required for application ‘MP3 Encoder C’ was deactivated, because it needs to be validated”.
I’ve tried to validate it but still doesn’t go.
Do you have any suggestion? Thank you.