Is the error reported for this medium only or does it happen with papers too?
Related to the "LED". The Spectrometer used in the Z models is more like the Isis than the Eye One and it is the light source, a white LED, that is used by both and not in the Eye One. Your "LED" error could point to a problem with the spectrometer or to an imcompatibility of that LED lightsource with the canvas if it does work correctly with paper.
One of the faults could be that canvas is too flexible to keep the right flatness/dimensions/position for the spectrometer reading. Either the spectrometer or the paper/head positioning sensor could give that error I guess but
check the Z3100 Service Manual available on the Wiki Z3100 pages for a better description of that error message.
http://z3100users.wikispaces.com/Z3100+problemsmet vriendelijke groeten, Ernst Dinkla
Dinkla Gallery Canvas Wrap Actions for Photoshop
http://www.pigment-print.com/dinklacanvaswraps/index.html