When you entered the 1099-R, you shroud have selected "Alternate payee under QDRO" as an exception to the penalty, but since you did not, you should call the IRS on the number on the letter and explain to them and then follow there instructions is they want you to amend and sent the amended return to the address on the letter - not the normal amend address or it will not answer the letter.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
