1. When I use the menu Gallery/Open nothing happen. I need to Click on Start and then use the button New Gallery...
Are you saying that 'Gallery -> Open...' (from the drop-down menu at the top) and the 'Open Gallery...' button (on the 'Start' tab) both do nothing but that both 'Gallery -> New' (from the drop-down menu at the top) and the 'New Gallery...' button (on the 'Start' tab) both work as expected?
If so, it sounds like something might be blocking the 'Select Gallery Folder...' dialog window from being opened.
If you have any security software installed on your computer, try temporarily disabling it (or make an exception within it for JuiceboxBuilder-Pro) to see if this makes a difference.
Normally, if there is a problem with the 'Open Gallery...' button, then there is a problem with the 'New Gallery...' button, too.
Several users who have reported such issues have been able to resolve their problems by closing JuiceboxBUilder-Pro and manually deleting the following folders.
~/Library/Application Support/Adobe/AIR/ELS/JuiceboxBuilder-Pro
~/Library/Preferences/JuiceboxBuilder-Pro
Also, please take a look at this forum thread in case any information within it helps.
2. Does the Juicebox license allows me to share the files (images, jbcore, thumbs, config.xml, index.html) of the galleries created with others people, for example zipped in a file to download, to use offline?
Unfortunately, the Terms of Use do not allow redistribution of the the source code (which is within the 'jbcore' folder). Here's the relevant quote:
Redistributing or reselling the Juicebox source code is prohibited.
A Single-Site license would allow you to use Juicebox in an offline environment (for example, in a kiosk at an event or on an intranet) but you would not be able to distribute galleries which include the 'jbcore' folder.