Probably way too late to answer this :P
But posting this for ppl looking for a solution
This is what seems to have solved the problem for my crashes since I started using bitdefender


1) Open BitDefender

2) Settings>Antivirus

3) Shield -> Turn off Active virus control

4 Antivirus> Exclusions

5 Add game folder etc to Excluded files and folders and processes(Also add windower if you happen to use that)

6) Firewall> Application rules add FFXI, windower etc

7) Settings> General> Game List > Add game

9 DOne!

10 Have fun!