[BitBucket user: asch99]
[BitBucket date: 2017-03-14.18:09:56]

OK, turns out a time-out occurs in dul.cc: DUL_ReceiveAssociationRQ()

The issue can be solved by patching the dul.cc file of dcmtk-3.6.0, just replace line 627 with the corresponding line in dcmtk-3.6.1:
old: cond = PRV_NextPDUType(association, block, timeout, &pduType);
new: cond = PRV_NextPDUType(association, DUL_NOBLOCK, PRV_DEFAULTTIMEOUT, &pduType);