Yes i used PDB calls from 2.8 so you will get deprecation errors in Gimp-2.6 most likely.
It should work fine in Gimp-2.8 however.
When you use the script try using it with just a white bg layer and black text on a transparent layer.
Just those 2 layers.
Molly i believe the drop shadow above your layers is the gloss shadow layer.make it invisible and see.
About coloring -
If you select the original image layer you can use Colors>Colorize to change colors for the body of the text or shape, or whatever you created.
If you select the top drop shadow layer and use colorize you can change the border color.
Don't go to far to the left with lightness setting (colorize), or you will blow out the gloss and make it darker.
This was actually an text layer i had ran my crayon-text script on.This was comic sans at one time.