Quote - On the prop staying stationary: This is a "gotcha" that gets everyone at first.
Poser uses Spline Interpolation by default, which means that any move you make between
two frames gets extended in a curvy way between the frames AND after the frames.
There are several solutions.    Easiest is to set the interpolation to linear for
this prop.  You can use the keyframe to do this, but it's tricky and time-consuming.
Here's a script that does it easily for the current prop or figure.

http://ockhamsbungalow.com/Python/SetRange.zip

On changing visibility:  You can do this in Poser 7 rather easily.  On the Properties
palette you'll find a little key next to the Visible choice.  Click on the key to turn it
green, and Visibility will become animatable.  It's an off/on choice, 0 for invisible
and 1 for visible.  When the key is green, the Visibility parameter will appear on
the keygraph and you can animate it.  In earlier versions, there's no clean way
to do this; you either have to scale the prop down to zero or move it way out
of the scene to make it invisible.  Whichever way you do this, it needs to be
a sharp move.  Let's say you want it visible at frame 40 and then gone at frame
41.  In the keygraph put the Visibility to 1 at 40, then pull it down to 0 at 41.

On SWF: Poser's internal SWF generator has never been very good.  Your
setup apparently has more trouble than most; it doesn't typically crash but
it does typically run very slowly at best.  No matter what the final destination,
AVI, WMV, or SWF, you're always better off rendering an animation to separate
frames and using some external editor to combine them into the movie.

Okay, I downloaded the file you linked to, but the txt file that came with it didn't tell me where to put it in.

As for the animation, considering that my last one went to 2300 frames, and was up to 1000 frames done before it crashed, would I be okay with doing small snippets of the animation in Poser, then combining them into one long animation with Windows Movie Maker or something?