Shoutbox

First of all, I'm really thankfull for the one making this program, and its really helpfull to me, so thanks.
Downloaded and installed the new Messenger Plus! 3.
Asks me if I regret installing some adaware, offcourse not, if the maker of this program can make some money out of this, I don't care.
But there is a difference between adaware(ie popups) and install a trojan downloader. Immediately after installing it tells me a Virus has been found in MsgPlusSetupFile-A.tmp ---> A trojan downloader
It's not a problem, I know how to remove it and keep MSN Messenger and Messenger Plus still working, I'm just wondering why a trojan downloader?

Note : I don't use some kind of free antivirus program but the best program at the moment.
I will post more details later.
It IS a trojan, and not some bad heurastic detected sponsor thing.