I looked at your file and made a few changes to it, hopefully for the better. Fixed The thumbs and the knees are better. I removed your smartskin, it didn't seem to work well and added fan bones for the elbows, knees and ankles. Also added an eye target for you. You have a problem with the A mouth pose, it crashes. I thought it was something I did, so I redownload and the problem is still there. Just delete the pose and start from scratch. Here's the file.