There is no step of the process that reports "generating tiles". What you should see is ICE report "Compositing for Photosynth". When that finishes the Photosynth uploader is automatically started and it will progress with "Uploading file 1 of
N", "Uploading file 2 of N", ... "Publishing Synth". The 'N' will depend on the size of your panorama.
My guess is that you are using the Photosynth App by itself and not through ICE.