I had this problem after a clean install of Mac OS and this is what worked for me:
1. Download the Sky Go installer.
2. Right click on the downloaded SkyGoInstaller file and choose 'Get Info'.
3. On the Get Info open tab, check 'Open using Rosetta'.
4. Open the SkyGoInstaller file and Rosettea should then install and afterwards, the SkyGoInstaller app should run and install.