I had some issues when I first started trying to place forest fire effects getting the XML files to compile with BGLcomp. Are you having similar issues? I could send you a working XML file if you like, then you could simply change the lats and longs of the effects and see if you could get it to work? Make sure that you have the scenery complexity level in the XML file set to the same or lower than what you use in the simulator. The XML file example for forest fire effects placements is set to normal (I think) if you fly with your scenery settings on anything lower than that the effect won't show up. I always use SPARSE in this setting, that way the effect will show up for almost everyone. Let me know if that doesn't work or if your having different issues and we'll get it figured out. You'll also have problems if you set up the effect to only show on a specific day and you forget to select that day in the simulator, sounds pretty obvious but that one has caught me before.
<SceneryObject lat="N54 50.75" lon="W127 24.39" alt="0" pitch="0" bank="0" heading="0" altitudeIsAgl="TRUE" imageComplexity="SPARSE">
<Effect effectName="fx_ForestFireLarge" effectParams="MOY=08,08;DOM=21,21;" />