"The Windows Installer Service could not be accessed"

Hello everybody!

I am not sure if this is the right subforum, but I didn't see where else to post it, so... Since I upgraded to Windows 8 Pro, I keep getting the error "The Windows Installer Service could not be accessed" when trying to install programs from an msi package. Unfortunately, Google is very unhelpful there - all known instances of this problem seem to have to do with windows 7 or XP, and most seem to be fixed by downloading and reinstalling the Windows Installer 4.5 redistributable, which doesn't apply to Windows 8 - the compatibility list on the microsoft download page ends at Windows Vista, and a search for "installer service" at the microsoft download center doesn't turn up anything when I limit the results to those applying to Windows 8. So I am kind of lost...

Screenshot of the error:


Any ideas? Am I the only one with the problem?

Thanks a lot in advance for any advice!