What version of Poser are you using?  P8/PPro2010 have IDL capability, but are restricted in technique.  P9/PPro2012 and later are much easier to work in.  A candle would be doable in P8/PPro2010.

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     Here are a few threads which I recall...

P8:  Making Biscuits Sparkle Glow! How?

Poser 9 - mesh as a light - how to do it?

How do I simulate torch light in an inclosed space?

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Poser 12, Poser 13, Poser 14, in feet.  

OSes:  Win7Prox64, Win7Ultx64, Win11

Silo Pro 2.5.6 64bit, Silo 2025.1, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5