[HELP] Cubase Studio 5 - Non Movable Hit Points

Cubase Studio 5 - Version 5.5.3 (32bit)
Windows 7 64bit

Hey all,
I have run into a very frustrating problem. When I double click on an audio loop in the cubase arrangement window to open up the waveform in the sample editor window and select the hitpoints, I can move the sensitivity slide and create the hit points.

However, when I select “Edit Hitpoints” and move the mouse cursor over any hit points downward arrow to move it, I get an “X” icon that says (Disable Hitpoint) and I cannot find a way that allows me to move the hitpoints manually to line up ones that around slightly out of place.

In Studio 4 it would just let me move them, but studio 5 just seems to give me the above

Please can you tell me what I am doing wrong and why I cannot move them manually, as have seen others so it in Cubase Studio 5?

Thanks All