I am having similar issues to PA3FBX, but I run everything under Linux, again with a Minitiouner Express, and using a script to drive Longmynd software.
I believe that it can not be down to using a Minitiouner Express rather than the Pro hardware as you are only sending a message to the software package, Minitiune.
The first line is from QO-100 WB Multi Quick tune version 0.9b to the Minitiouner software or in this case my script:-
“[GlobalMsg],Freq=10498733,Offset=9749458,Doppler=0,Srate=333,WideScan=0,LowSR=0,DVBmode=Auto,FPlug=A,Voltage=0,22kHz=Off”
Unfortunately I am getting no output from the Pluto with the latest alpha software. I am trying to fathom out if this is down to a different operating system or something else such as blocked ports etc. Or my settings.
I drive direct to the PC's own address, 192,168,1,194 and use port 6789. The gateway is 192.168.1.254.

Adrian