WARNING: rtmpdump/flvstreamer 1.8 or later is required - please upgrade

[conrad1on]

Okay, fixed it.

Turns out diddling with the 'Path' 'System variable' in 'Environment Variables' was indeed the issue, and manually adding C:\Windows and C:\Windows\system32 back to that would seem to have solved the problem. I've no idea what other possible paths may have been listed there that are now missing, but I guess I'll find out at some point when something else mysteriously stops working.

Thanks for all the replies to this though.