Circle Development is the previous sponsor program of Messenger Plus! Live, it is an
optional adware program, NOT malware.
In fact, the installer for CiD isn't included in Messenger Plus! Live anymore as it has been replaced with a sponsor toolbar courtesy of Ask/Conduit. It is just the uninstaller which remains to help people remove the previous sponsor if they have old versions.
There's an ongoing problem with NOD32 as outlined here:
eset nod32 blocked messenger plus 3.85
I can guarantee you that Messenger Plus! Live contains no malware/viruses/trojans