Newer Mac computers use Gatekeeper to prevent the installation of malicious software. The default Gatekeeper setting only allows the installation of software from the Mac App Store. There are two ways to work around this security setting.
The preferred solution on Mac OSX 10.7.3 is to (a) use Finder to locate the jMetrik installer file, (b) press the Control key and click the installer icon, (c) choose open from the shortcut menu, and (d) Click Open. Your computer may activate a virus scan automatically. Let it run to completion or cancel it. Your computer may also prompt you for your password one or more times during the installation process.
The alternative solution is a system wide change that may leave your computer vulnerable to malicious software download from the internet. For this solution go to Apple menu > System Preferences…> Security & Privacy > General tab. Under the header “Allow applications downloaded from:” choose the options “Anywhere.”
See the Gatekeeper webpage on the Apple website for more information on changing the setting. Note that this fix is a temporary solution and it leaves your Mac vulnerable to malicious programs you may accidentally download form the internet.