Try this.
(set! nextcolour (list (+ (rand 254) 1) (+ (rand 254) 1) (+ (rand 254) 1))) ;Random colour - not B, W or flagcoulor
(while (= (listeql? nextcolour inFlagColour) TRUE)
(set! nextcolour (list (+ (rand 254) 1) (+ (rand 254) 1) (+ (rand 254) 1)))
)
)
(begin
(set! nextcolour (car (gimp-palette-entry-get-color inPalette palettecount))) ; next palette colour, - not B, W or flagcoulor
(while (or (= (+ (car nextcolour) (cadr nextcolour) (caddr nextcolour)) 765)
(= (+ (car nextcolour) (cadr nextcolour) (caddr nextcolour)) 0)
(= (listeql? nextcolour inFlagColour) TRUE))
(set! palettecount (modulo (+ palettecount 1) numcolours)) ; increment palette
(set! nextcolour (car (gimp-palette-entry-get-color inPalette palettecount)))
)
(set! palettecount (modulo (+ palettecount 1) numcolours)) ; increment palette
)
That's from Rob's script.
I won't tell him. Her. I mean Wilber. Not Rob.