Other people have previously indeed reported that their antivirus program gave warnings of a trojan being present in Messenger Plus!. However, the virus warnings and/or spyware warnings some (antivirus) programs (mainly AVG) give, are not true; these are false warnings.
It is understandable that you are a little worried when you see such a warning, and that you will not believe me right away when I say that the warning you see is a false one.
However, I do hope that after reading
Note about Trojan detection, you will understand that the error is not true. It might help knowing that you are not the only one who reported it, so it's an easy mistake to make
/ 
