Installing Pro Tools Express on Mac Book Pro

I purchased the ProTools Express with the Fast track Duo and UPSupport plan from Sweetwater. I am currently unable to install PT because I'm getting following: "An incompatible version of the OS was found. Pro Tools 10.3.4 requires Mac OS X version 10.7 or higher." I am currently on OS X Yosemitte 10.10.3. The installation process fails and closes out any assistance is very much welcomed