I can only suspect that ur antivir is interfering.
Bossland has a support wiki for those kinds of problems.
BosslandGmbH:HelpDesk:Programs that Interfere with BosslandGmbH Products - The Buddy Wiki
BosslandGmbH:HelpDesk:AntiVirus Interference - The Buddy Wiki
go to the plugins tab and click on trinity settings.
on the general pane u have an option called elite monster, there u click on customize.
just check rare and champions.