When I export the Moho Tutorial 6.3 file to Flash and then open it in my browser, the browser crashes. Here is the crash report from Console when using FireFox:
Check out the section in the Moho Manual: Reference>Flash Tips.
It states that particles can be exported:
"particle layers (careful - a complex particle effect can easily overwhelm Flash)"
From the manual:
"On the other hand, some things in Moho are just not compatible with Flash, and cannot be exported to a SWF file. The following list covers the most important of these objects and effects.
* brushes
* fill and line effects (except gradients)
* layer effects (shadows, shading, layer blur, motion blur, etc.)
* image warping or 3D movements in image layers
* image layers that use progressive JPEG images (Flash can't handle progressive JPEG images)
* layer masking
* 3D layers "
Perhaps the item that you made into a particle falls into not compatible list above?
If I reemember correctly, a Flash movie has a hard-coded limit of 65,536 ( or thereabouts ) "objects" per Flash file. The sub layers of the particles aren't Flash optimized (look for the misssing "little red dot" next to the vector icons for the individual particles), so each frame creates a new Flash object for each particle. Just the Smoke layer in the tutorial ends up with 72000 objects (144 frames x 500 smoke particles), so right there the Flash player has an attack. In the Particles tab of the particle layers settings, turn down the particle count and you should be okay for Flash export.
Because much of the animation in Moho works in a very different way from Flash, Moho is often forced to export animation frame-by-frame in a not-efficient-for-Flash kind of way. Things like particles and variable line widths can easily exceed the limits of the Flash player.