When you say it crashes, what do you mean, Damia? Does the program close or just simply get stuck on the publishing step?
If you are simply seeing the progress bar stop at the Publishing phase, then please refer to this discussion (pay attention to how long ago the messages were posted and you'll see the recent conversation about halfway down).
David Gedye (the head of the Photosynth team) has posted some updates on what was going wrong and posted only minutes ago (as I write this message) that the problem is now fixed.
Hoping you'll try again soon,
Your fellow photosynther, N