after loading your blank object into poser, go into the material room, use the picker tool over the window that is visable that has your object in, and click on your object (just makes sure that it is selected) then left-click on the icon next to "diffuse color", and select "new node", (new window pop-up) come down to "2D textures" ( new window pop-up), come down to "movie" click on that and it will attach a movie node,

now on your newly attached node, click on the word "none" next to " video source", then locate your avi and load it in. after that come out of the material room by clicking on the "pose" tab (next to material room tab)

now depending on how many frames you need, you need to make your anim as long as that, so, click on the window tab at the top of your poser screen ( if your animation pallette isnt open by default) then check "animation controls" now you have your animation pallette open.

now on your animation pallette you will see frame 1 (in box) of 30 (in box) so if you need a 300 frame animation say, then click on the 30 ( in box) and change that to 300 ( or whatever you need) 

(this is for a static prop animation by the way, if you want to animate the object aswell, you''ll have to work that bit out for yourself, or just ask how to with want you want to do type questions)

ok, so we have an object, with an avi texture attached to it , and the correct timeframe that we need, so now you want to render the movie.

first you need to adjust your render settings, so click on the "render" tab at the top of poser, then click on "render settings", now with "auto settings" selected slide the bar up to the "final" marker, then check (put little blue dot in) the "manual settings" icon, should change that window, now click on the "aquire from auto" button on that new looking window, then uncheck "texture filtering" , then click on " save settings" down the bottom.

now, (nearly there) click on the "animation" tab at the top of poser,then click on "make movie" now you have a movie settings window, click on the arrow next to the word "renderer" and select firefly from that menu, write in what resolution you want the results to be in (width, height bit( remember to uncheck "constrain aspect ratio if you have a specifis resolution in mind)) , check that your time span is right number of frames, then click make movie.

(last bit)select where you want to save that new .Avi to, and what you want to call it, save, then you will get a " video compression" pop-up, go with the microsoft video 1 compressor, and slide the "compression quality" bar up to 100% ( no compression) , then click ok,

now just wait for your .AVI to render.once finished it should auto open in windows media player, or prabally whatever you have as your default player.

all done, cup of coffee time.