It's possible that despite setting Bitdefender to allow the casino, it is still blocking the tournament. It may be blocking it from "calling home" to the tournament server, as this is the behaviour of a Trojan as well as a casino client. It's a different kind of block, so may be a "silent block" rather than one where Bitdefender asks for your choice.
There are, however, other problems related to Microgaming tournaments that can have similar effects, such as the tournament server not responding, which would be seen as the game not quite loading 100%, but getting stuck whilst waiting to connect.
I have also had trouble from various security products, and it seems not all casinos are affected equally, even where they share the same software.
