I haven't been able to install Building Design Suite Premium 2014 on my PC if BitDefender 2013 is present.
Does it have to be like this?
It is *always* recommended that anti-virus software be disabled during the installation of Autodesk products.
The problem is with BitDefender Total Security 2013 - because of it's anti-tamper feature - it can't be disabled ...
Antivirus programs that prevent you from doing normal work are not good solutions. You might check if there is an admistrative setting to temporarily disable the protection. In my professional experience, anti-virus software do not stop viruses anymore. That is why I no longer run them. Their lock downs and memory hogging themselves are akin to a virus.
I wouldn't go quite that far - our system caught something serious last week. But another system falsely identified some AutoDesk components causing the program to be disabled by the fix. So any sort of protection scheme shouldn't be used as a blunt tool, otherwise there will be collateral damage.