Toyota's website is, frankly, a piece of shit.
I have that exact problem sometimes. Best I can figure, if you check multiple boxes, it won't save. Try just checking one box and detailing the other items in the notes; or inputting multiple entries, one for each check box.
My wife's Prius, the dealer ****ed up the odometer entry during her last free service and now the website reads 100,000 miles more than the car actually has. We can't correct it ourselves because it keeps defaulting to the wrong reading, and Toyota won't correct it without the dealer's input. It's not a big deal, but it's a freaking aggravation. If Carfax gets a hold of that before the dealer fixes it (and they haven't yet) then they will list an 'odometer discrepancy'.