Hey seifdune, I dont know what you are trying to do. But i had the same issue a couple of weeks ago. If you want to create corrective blendshapes you should take a look at the pose space deform workflow. It is great and works completly procedual.
When your scene is crashing you should try the tool with a simpler test-setup. Create a fresh scene then make a cylinder and deform it with two bones. There is a pose space deform shelf tool. Use this and follow the instructions.
Ok thanks. How about mixing more than two blendshapes for facial rigging. Two work fine but when i add the 3rd blendshape the result become weird and broken.