Problem Connect Message Ports in GNU Radio 3.7.9

[joary]

Hi, First of all congratulations for the great work!

I was testing the following setup on GNU Radio 3.7.9:

But I get the error:

Traceback (most recent call last):
  File "/home/jp/Work/Freelancer/grc_sat_trx/grc/top_block.py", line 112, in <module>
    main()
  File "/home/jp/Work/Freelancer/grc_sat_trx/grc/top_block.py", line 100, in main
    tb = top_block_cls()
  File "/home/jp/Work/Freelancer/grc_sat_trx/grc/top_block.py", line 73, in __init__
    self.msg_connect((self.blocks_socket_pdu_0, 'pdus'), (self.framers_gr_hdlc_framer_b_0, 'in'))    
  File "/home/jp/Work/Freelancer/install/lib/python2.7/site-packages/gnuradio/gr/hier_block2.py", line 59, in wrapped
    func(self, src.to_basic_block(), srcport, dst.to_basic_block(), dstport)
  File "/home/jp/Work/Freelancer/install/lib/python2.7/site-packages/gnuradio/gr/hier_block2.py", line 131, in msg_connect
    self.primitive_msg_connect(*args)
  File "/home/jp/Work/Freelancer/install/lib/python2.7/site-packages/gnuradio/gr/runtime_swig.py", line 4216, in primitive_msg_connect
    return _runtime_swig.top_block_sptr_primitive_msg_connect(self, *args)
RuntimeError: invalid msg port in connect() or disconnect()

Altough, if i disable the Socket PDU blocks the flow-graph runs fine.
It also runs fine when i connect the Socket PDU's directly.