The only thing I can think of that may have caused this then is one of the sponsors in the setup being detected as a false positive =/
As I'm not clear exactly which setup was being used (there are a few), I'm not going to be able to narrow down a cause.
The best bet is to download directly from
http://www.msgplus.net or to use the automatic-update feature within the software. You should also check that when you open the setup file (if you do download), that it is signed as below: