Hi Arthur.S,
The problem you're having is due to NOD32 blocking Messenger Plus! Live for unknown reasons.
See
Menthix's reply to Nod32 Blocking Update URL.
Menthix and others worked hard to remove any problems the anti-virus companies were detecting and ended up with good results, however at present NOD32 is the only one that continues to
detect Plus! as a problem. Once they're made aware that the problems have been removed, they should change it.
But until then, my recommendation would be to remove NOD32 and use a different anti-virus such as
Microsoft Security Essentials.