I got Stony to take a look and here's his response.
Shapeways has a limit on uploaded models of 1 million triangles. Yours is at 1.5m and you need to try to reduce that some.
I believe that the upload process still has an issue that if you upload a model with more than 1m triangles, the background processing software aborts without producing a usable message.. hence the blank email.
Personally, I'd remove a LOT of the holes around the edge and such, but another option would be that you seem to be using 20 facets per circle, if you dropped that to 8 or 6 facets per circle, it is likely that you'd not be able to see the difference (these are VERY small holes), and it would drop a significant number of triangles out of the file.
A few notes ...
1) your "C" beam supports under the model are too thin. They measure out at 0.19mm thick and that will be rejected upon printing.
2) the "X" cross-supports are not 'connected', they are floating independently. that makes for 56 very small parts that the operator will have to pick out of the printer with tweezers, and a number of them are likely to be lost. Did you intend for those to be separate parts? If you do weld them to the main body, I'd consider removing the holes in the end of each beam.. again, those holes are contributing to the overall triangle count. Otherwise, you need to try to do something to collect them together in one area and sprue them together such that they don't get lost.
3) in the center of your model, you've got a bit of bad geometry that will fill in as solid and cost you more. The Boolean join you did for the hole under that center "knob" failed.. it needs to be redone.
4) the main 'skin' of the model (the part like the fabric on a umbrella) is also too thin. You've got it at 0.1mm and it must be at least 0.3mm thick.
Also.. printing this is going to be rather expensive:
http://stonysmith.com/wired/VolumeEstimator.asp?L=481&W= 481&H=30&T=.3