Are you able to call your sup and/or schedule phone conferences? This person is probably very busy supervising other dissertations, teaching classes, having a life, etc., so it's important that you take the initiative to communicate. I would keep working on finishing the corrections, but at the same time, keep calling and emailing - frequently! You might feel like you're nagging, but remember the adage "out of sight, out of mind." You need to know if your corrections are sufficient, and you're working within a short time frame.