Scroll lock OSX Nomad

Which version of software are you on?

If 2.3.X it's, Function F8.

Version 2.3.1.9.0.12

Fn F8 seems to toggle "command edit mode: F8/Ctrl8 to disable"
these words appear in red above the command line....

I'm not sure I understand the problem you're seeing if it's not the editing mode. I don't think Scroll Lock on or off stops you editing effects.

You know if you go to the top right corner you can drop now a virtual keyboard.

I also got the same message off my RVI and have no idea what it means.

which message did you get? the "command edit mode" one?

Command Edit Mode: F8/Ctrl8 to disable

this refers to two different methods of how to enter commands into the command line. if this red text is NOT present, then you use an external keyboard and hotkeys to enter text. it's like pressing actual buttons on a facepanel. so e.g. q will write Cue.
if there is red text, then you can actually type commands letter by letter. to get the word Cue you would actually type c, u, e.

to change the behaviour you press either F8 or ScrollLock on an external keyboard. there is also scrollLock on the facepanel but that one is for something else.