I was getting tons of memory access violations with 1.1 (with 0 with 1.0). After thinking about it during my sleep, I figured out my cause. I don't know if it relates to you, but here was my problem.
I had a separate thread that was doing the rendering of the device. During which that thread was still active, I was reDimming (re-initializing) my variable used for the device. Once I put a variable to cancel my render thread, it was able to break out and close that thread, then after re-initalizing my device, I started the thread back up.
I also got this type of error when doing Remove on the root node to remove everything from the scene. Somehow the remove was removing it at the same time the thread was trying to draw it and it was out of sync. Trying to read from memory that wasn't there, etc. Once I stopped that separate render thread, it fixed this also.
I just added a member var of isRunning and exited the render thread when = false. I also made sure that the Render loop/thread didn't start until after I have added all of my scenenodes. Seemed to have a problem of adding/removing scene nodes on a different thread than the rendering.
I don't know if that helps, but if you are using threads like me, then it may help