SoC Builder: "Build Software Application" fails due to Cannot propagate non-bus signal to Task Manger UDP Read Event

I am trying to build a SoC design using the SoC Builder. The Build software application stage fails with the error:

Cannot propagate non-bus signal to block 'WS_SoC_top_sw/Task Manager/DIS_UDP_ReadEvent' because the block has a bus object specified. A bus signal matching the bus object specification must be passed in.

WS_SoC_top_sw is the auto generated model produced by the SoC Builder.

In my source model I have:

I cannot determine how to ensure the correct event message is pulled in to the auto generated model for onward code compilation.

Does anyone have any pointers on what I have wrong here?

Thanks in advance

Graham