OK, brand new 8x45.obj and 8x45.x3g files which definitely works in makerware. Sorry for the issues. Good to go now though. These are 8x4.5 props modelled on the ones found on the witespy quad page.
I have not used these myself yet. Don't have a printer yet, but please download this and let me know if they worked for you.
Centre hole is 6mm.
Please let me know if you have issues with any of the files, I WILL fix them if you notify me.