Network Queue Error

[philw]

Keyshot 5.3.6 Mac
Network client 5.3.1
OS X 10.11

Since (I think) upgrading to El Capitan, I now get an error when the network queue is launched (see attachment). Network Master is an unchanged Win7 machine. Render queues work and get processed but I can't access the finished results as I previously could

Any ideas ?

Many thanks.