Greetings.... Mr. Frondie

I doubt that the lack of SP2 would cause ZA not to install.
I have been using ZA Pro ver. 6.1.737 for quite a while now and up until recently, I didn't have SP2 installed. It would update properly and I have installed new versions etc.

What exactly does the error message say? How does the install go...does it finish and then not let the program start, or does it just not execute the installation process?

Try also here:
Programs that are known to experience...