Starting with 10.8, OS X includes a feature called "Gatekeeper". Gatekeeper is designed to help keep malicious software off of your Mac by giving you more control over what you install. However, you may need to bypass Gatekeeper to install Panorama on your system.

To do this, start by right clicking (or Control clicking) the
Install Panorama icon.

Next, select
Open from the top of contextual menu that appears.

HT5290-Contextual_Menu-001-en

A dialog similar to the one shown below will appear. Click
Open in the dialog box. If prompted, enter your administrator name and password.

HT5290-Exemption_Dialog-001-en

From this point forward you should be able to continue the installation normally.

For more information about Gatekeeper, see these links:

http://support.apple.com/kb/HT5290

http://www.bu.edu/infosec/howtos/bypass-gatekeeper-safely/