An interesting tool, I think I must have passed it over on Hivewire. It's not listed on Nerd's Store page but I find it's now at the Marketplace as https://www.renderosity.com/marketplace/products/147068/rain-tool but lacks the specs it had on HiveWire. For the sake of future searchers, here are the specs as a screenshot:

I can't offer any advice on workarounds for animation glitches. Other than to consider rendering separately as an overlay layer, cutting out the glitchy frames (if that's possible) in a video editor, seamlessly looping, and then compositing the result loop over the scene in a video editor. 

But I would be interested to know what recent version(s) of Poser it can successfully run on. Can you say what version of Poser you're using please, and perhaps post a screenshot of the glitch?

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