Problem printing from Aperture to Epson R800

I use Aperture 3.4.3 and an Epson Photo Stylus R800 printer. I can print small format photos, but when I try to print at A4, even using Epson's own recommended 255g paper, I get the following message: Paper Out/incorrect output tray position. On Epson's recommendation I downloaded their Easy Photo Print software and that works fine, which suggests the problem lies with Aperture. Can anyone help?

Also, I would welcome any suggestions as to what to use when Apple abandons Aperture. I don't need the most sophisticated photo software.