A couple of issues

[MnM]

Excellent, thanks Simon. I'll experiment with allowing the system32 version of javaw.exe through the firewall (hadn't appreciated the firewall discriminated so finely), as that may well have been the problem. If that works, then I guess using the system32 version must be the right way to do things: the benefit is that it's always the latest version, and so the task scheduler action would no longer be tied to a particular java release. The scheduled task wouldn't then need to be changed following any upgrade to java 8, for example.

Also if using the system32 version of javaw.exe, I think the scheduled task could just be changed to exactly the same command as used by the minimserver shortcut, which would be (trivially) a little tidier:

Program/script: mserver.jar

I'll give it a go and report back.

Thanks,

Matt