Well Hans, thank you very much for your help. A couple of things about building apps problems.
1- Your fix made the folder to be named always "app-auto-load", write? Well, that fixes the bug, but completely kills all the references of the "../FOLDER_NAME/FILE" form in the patch, creating a new bug (I think). What do you think about it?
2- I accidentally saved the app in the same folder that was being built into an app. The result was a recursive app with itself inside itself inside itself…I had to force PD to quit. May be there should be a protection or at least a warning message.
Ignacio