How are you making the rendered movie?  My suggestion is to use animation>make movie and set it to render a series of PNGs, which you would then compose into a movie.  Set format to image files, and set renderer to Firefly.

     If you render a still (a single frame), do you see the AVI texture on the dragon?  Are you rendering in Firefly (rather than in preview)?

     As a test, you might add an image map node, plugging it into the ambient color socket.  Set the ambient color block to white.  Set the ambient value to 0.25 and use a checkerboard image for the image map.  Render that.  This will check to ensure that the dragon has not somehow lost its UV mapping.

     I use the movie node a lot to make animated textures, so I can assure you that the concept works.  I use it animate displacement to produce water ripples and flickering flames, animate transparency for bursts of pixie dust, and animate color for radar screens.  We just have to figure out what is going wrong with your workflow.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

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