Divorce decree statute of limitations

Six years ago my ex wife and I had a very amicable divorce. In the divorce papers she was awarded 50% of my 401K. However, in the last 6 years she has made no effort to remove her portion of that money from my 401K. Due to the economy my 401K suffered greatly and the amount in there now is less that the time of divorce. I have not removed any money though. My question is can I compel her to remove the 50%? Can she take the rest of her life to move it? If she does move it do I have to pay her the amount that would have been 50% at the time of the divorce or has she lost all rights to the money at this point?

You may have the QDRO drafted pursuant to the Agreement the funds will be transferred.