A small number of users have a crash when selecting the ruler stencil currently. We have not managed to reproduce the problem here so we don't surrently know what causes this. It may relate to the fonts on your computer or some other cause.
A couple of things which may help. One recommendation from another user 'My problem has mysteriously cleared up. I clicked on a half dozen stencils to open them. Then I did a click/drag on the ruler and was able to drag it onto the canvas. Thereafter, I was able to click the ruler stencil in the stencil drawer and open as many rulers as I wanted.'
Also, try closing down any background programs you may have running, then launching ArtRage and seeing if you still get the problem. If you still find that you are seeing the crash, choose the option to 'Send information to Microsoft' as this may enable us to get more information on the problem. Also, you can email me directly at firstname.lastname@example.org and I can do some work with you to see if there's anything else which may help.