For those who are having the problem when they kill a boss in an instance and are almost instantly teleported out without being able to pick up the items, the solution is as follows:
Go on Config.java file and exchange this:
INSTANCE_FINISH_TIME = generalConfig.getInt("DefaultFinishTime", 5)
for this
INSTANCE_FINISH_TIME = generalConfig.getInt("DefaultFinishTime", 300) * 1000;
The first number is in milliseconds, and you need convert do minutes, so, 300*1000=300000 = 5 minutes (Retail like)