Sorry...still not working...used the newest Beta 1.56.5 and the new IB.dll
Error message slightly different though....

Download compiling..........
IB.dll => Interactive Brokers plugin mounted
Login Interactive Brokers..
!IB Socket connected
!Account DUxxxxx at UTC 24.04. 07:13
Download...
Error 053: DAX-FUTX-20170317-FDAX-DTB-EUR unavailable at this time
!DAX-FUTX-20170317-FDAX-DTB-EUR 01.01. 00:00:00 to 24.04. 07:15:13 failed history unavailable!
Error 056: Can't download DAX-FUTX-20170317-FDAX-DTB-EUR 2017 history
No bars generated
Logout.. ok