instal problem

Hi,

I am new to Mac, having recently changed from 20+ yrs with PC to a 2011 iMac 21" running OS X Lion 10.7.5 WOW, what a stepup from the old MSDOS days!

I am a heavy Excel user so the obvious first chore was to instal MS Office for Mac 2011. That installed very easy and I am extremely pleased with it. However it will not run one of my heavily macroed spreadsheets which includes about 15 workbooks, all linked with VBA etc. The problem appears that the Office for Mac will not handle ActiveX in Excel. So I neeed an alternative...

I have installed Parallels 9 and in the process of installing Office 2013 Professional but have run into a snag. I have downloaded the iso file for the instalation but keep getting this error:

I would be extremely grateful if someone could direct me along the correct path. I have spent many frustrating moments with a pile of Mac books but am stumped.