Using Yosemite 10.10.3, Macbook Pro

After I installed the update 14.5.2 my Outlook won't open. When I contacted tech support they directed me to install the prior update 14.5.1 but my computer won't accept that version for some reason. Not sure what to do next.

I also want to back up my data file for Outlook so if I end up reinstalling the whole program it will open my current data/email folders etc. Not sure how to do that without being able to open the program.