Hello Christoph,
Per the logs you have provided, problem is here:
*** ERROR => NiIDgHdlGroupAdm: failed to join 224.0.0.129 on interface 0.0.0.0 [nixxi.cpp 9572]
*** ERROR => RqQInit: NiDgHdlJoinGroup failed (rc=-10) [dpQueue.c 1559]
*** ERROR => DpIPCInit2: RqQInit [dpxxtool2.c 514]
*** DP_FATAL_ERROR => DpSapEnvInit: DpIPCInit2
*** DISPATCHER EMERGENCY SHUTDOWN ***
This is a known issue discussed in SAP Note - 1932555. Please refer the same for cause & solution.
Hope it helps.
Regards,
Shahid Ahmed