If you are having trouble installing JuiceboxBuilder-Pro, then please see the Installation Issues section of the JuiceboxBuilder User Guide.

If you are having trouble installing Adobe AIR itself, then please take a look at Adobe's own Troubleshooting AIR Installation | Mac OS support page which should hopefully help.

If you continue to experience difficulties, then there is a fairly comprehensive list of things to check and try in this forum thread.

Hopefully the information in the links above will help to you successfully install JuiceboxBuilder-Pro.

Edit:
I notice in the Adobe forums that other users seem to be having problems with AIR and AIR applications under Yosemite so Adobe may be currently having issues with AIR on the new Mac OS.
You might like to try using the latest beta version of Adobe AIR which can be downloaded from here: http://labs.adobe.com/downloads/air.html
You could also try reverting to an older version of Adobe AIR (such as v14) to see if this helps. Older versions can be downloaded from their archive web page here: http://helpx.adobe.com/air/kb/archived- … rsion.html