Thanks for your kick answer (even when I took a lot of time for answering you back).
Following what you said, I was trying to install both of the offline servers you said, but I couldn't, so, searching how to do it I found a YouTube video (
https://www.youtube.com/watch?v=KITcCSiFqC4) where they explain how to install the Ai2 Starter (I dont even know if is another name for one of the option you give or if is another product). Well the video worked. I have App Inventor running offline.
The matter is that when I try to import .aia file of my App created on
http://ai2.appinventor.mit.edu/ I got an error because the version on the website is newer and when I import it on the older version (the offline one) it does not work OK.
The Question: Do you know how to update the offline version or another way to make my App work on the offline version?