LAS VEGAS (AP) _ O.J. Simpson says ``cumulative error'' during his trial last fall should be enough to overturn his armed robbery and kidnapping convictions. His lawyers have filed an appeal with Nevada's Supreme Court. Appeals in Nevada can take more than a year. Simpson's filing claims judicial misconduct, insufficient evidence, a lack of racial diversity on the jury, and errors in sentencing and jury instructions. His lawyers says the cumulative effect was ``egregious and prejudicial.'' Simpson was sentenced to nine to 33 years last December for confronting two sports memorabilia dealers in a Las Vegas casino hotel room in September 2007. He argued he was trying to retrieve stolen property.