Lerpz Tutorial Texture Rendering Problem

Having downloaded the Lerpz free platforming tutorial from the asset store and during the course of working on the tutorial I have found a problem with Unity's texture rendering. In the tutorial starting on page 22, you go through the process of creating the main character's jet pack by adding a point light and two particle systems to the Jet game object (one for each jet on the jet pack). The particle systems' are each composed of: An ellipsoid particle emitter, a particle animator, a world particle collider and a particle renderer. In the particle animator component settings it is neccessary to adjust the colour of the animator to 4 varying colours from light yellow to black to emulate flame. Once the other settings have been adjusted (such as the frequency of the particles being emitted), each jet should release a steady stream of primitives textured with the appropriate colours to give the illusion of a flame emitting from the jet. However having made all the neccessary adjustents, I find that the jets are emitting a steady stream of purple coloured primitives shown in the attached image and I'd like to know why this is happening?