Hey James,
Holding CTRL should be erase mode, releasing CTRL should exit erase mode.
If you are stuck in erase mode it may have something to do with the button settings on your tablet or the emu3butt.
You could try click and hold on the annotation tool in the tool bar and move the pointer to Annotate and release the click.
You can use the pen on your tablet or the mouse.
Hope this helps.
