Updating DAS Trader Pro to new version :
After updating "DasTrader Live Account" (Tools -> Auto Update) to version 5.7.5.6 , I was not able to launch SIM by clicking "DasTrader-SIM Account".
So, I copied DASTrader.exe from "DasTrader Pro" and pasted into "DasTrader Pro_Sim" folder (replaced old DASTrader.exe) and now my issue is resolved.
So every time after updating DasTrader LIVE , copy the .exe from folder "DasTrader Pro" paste it into "DasTrader Pro_Sim" (replacing the old .exe). It works great !!