I heard that some people were getting "Error 16" when trying to make an outgoing call after rooting. I had not experienced this after rooting (I tested when I heard people reporting this). But today, after I did a factory data reset, I had this problem. Made a call, and I got error 16. I stayed on the line, and a Sprint rep fixed it. So, for now, I'm going to blame it on the root and factory data reset combination. Just a heads up.