Comment 8 for bug 1222233

You seem to have installed a number of i386 kernels in addition to your amd64 ones. It seems this is causing an issue with the release upgrader.

linux-image-3.5.0-17-generic 3.5.0-17.28 0
linux-image-3.5.0-23-generic 3.5.0-23.35 0
linux-image-3.5.0-24-generic 3.5.0-24.37 0
linux-image-3.5.0-25-generic:i386 3.5.0-25.39 0
linux-image-3.5.0-26-generic:i386 3.5.0-26.42 0
linux-image-3.5.0-27-generic:i386 3.5.0-27.46 0
linux-image-3.5.0-39-generic:i386 3.5.0-39.60 0
linux-image-3.5.0-40-generic:i386 3.5.0-40.62 0