Hi graywolf,
You are correct, the machine in question did not have a mouse connected to it at the time (it is an HTPC machine, and boots without keyboard/mouse because they are bluetooth and only activate when needed).
I can tell you that 4.2.25 fixes this…sort of. If I boot with a mouse/keyboard originally connected, then disconnect them, I can then remote in from another machine (although I get an old X-window style cursor instead of a windows one, but no problem).
Unfortunately if you boot the machine with 4.2.25 installed WITHOUT a keyboard and mouse present, nomachine crashes badly at initialization, and keeps crashing continuously if you acknowledge the dialog box, even after you have re-attached a keyboard and mouse.