I'm using the Plugin and when I press the Backspace key on my keyboard to erase something I have just drawn, the browser takes me back to a previous page!
This is not a ChemDraw specific issue. This is a browser issue. You would see the same problem with any plugin, not just the ChemDraw Plugin. The keys on your keyboard are mapped to the browser application, not the Plugin. The only way you can access the commands of the Plugin are to either use the ChemDraw toolbar or right click (control - Click for Mac users)to access the ChemDraw Plugin menus. So in this case you could either use the eraser tool on the toobar or right click on the selected object and choose Clear.