In 2010, Ohio election law was amended to require all parties to certify the names of their Presidential and Vice-Presidential nominees at least ninety days before the general election.
The Ohio law is section 3505.10(B). It says the November ballot will include
the names of the candidates for president and vice-president certified to the secretary of state or nominated in one of the following manners: (1) Nominated by the national convention of a political party to which delegates and alternates were elected in this state at the next preceding primary election. A political party certifying candidates so nominated shall certify the names of those candidates to the secretary of state on or before the 90th day before the day of the general election.
Texas had a similar problem in 2008. The law required the names to be certified earlier than the date of the Republican and Democratic national conventions. The Secretary of State did not enforce the deadline, and in 2009 the Texas legislature repealed the deadline.
The Ohio legislature is still in session, so it could fix the problem if it wished.
Via Ballot Access News.