I also just found a typo in ALL my statements.
There is a paragraph-ending sentence that had no period and just hangs there, like this
Also, I found an even more serious typo in my resume, which also got sent to all the schools. Go figure. Of course I also read both the statement and the resume approximately 10,356 times before submitting.
But I have gotten an acceptance from one school and an interview from another, so I guess it isn't a deal breaker. Don't despair!