I've spent quite some time trying to set up an animation render with the exporter. Finally, it works for me, on blender v.2.55, at least for a simple scene.
I make this topic to attempt to summarize the different steps, centralize some informations and avoid you guys to make the mistakes i've done.
Hopefuly it'll save you a bit of time searching for infos here and there on the forum.
-1- First of all, download the official 2.55 release of Blender on http://www.blender.org, (the other builds found at graphicall.org didn't work for me).
-2- Get the 2.54 exporter by enricocerica on this thread : http://www.refractivesoftware.com/forum/viewtopic.php?f=32&t=4035&start=0
-3- Open the .py file and in two different places of the file (currently on lines 997 and 1817), you'll find a variable name called "oct_export_samples_per_image_presets" change it to something shorter, like "oct_export_s_per_i_presets". ( I found this info here: http://www.refractivesoftware.com/forum/viewtopic.php?f=32&t=4280&start=0 )
-4- Now save and copy the script file to your \2.55\scripts\io folder, in the blender'directory.
-5- Run Blender, open any.blend file and choose render/octane, the blender's render panel should now display options for Octane.
-6- please remember that all the files paths must be absolutes , i.e you have to enter the full name of the path.
-7- The first path is the absolute path to your octane program, for example on my computer it's C:\Program Files\OctaneRender_pre23_5\octane.exe
-8- The second is the absolute path to the directory where your .blend file is (no need to type the .blend name in it) for example : "D:\3D-blender\scenes\anim-test"
-9- make sure the files paths don't contain spaces (i guess nor any exotic types such as accents) My blend project was located in a folder called "3d blender", and it provoqued an error at some point, i renamed it in "3d-blender" and it worked fine.
-10- If Export Sun is checked, you have to define a light source, otherwise uncheck it, in my opinion it's nicer to manage the lights directly in Octane.
-11- The third is a custom string that the script will use to name your obj. and .mtl exports. example ("my_obj_scene") no need to enter the ansolute path of anything here, just a name.
-12- Hit "Render", that will export the .obj, .mtl and create the .ocs file
-13 - Octane should have opened itself and start rendering, edit your scene to make it nice and beautiful : add some materials, nodes, change the lighting and the sampling (please note that the sampling value set in Octane overrides whatever you can input in blender). Save it as is.
-14 - Now, if you want to render an animation, you can set the frame range you want, and a valid directory (once again don't use any space in the folder's name) and hit "render animation"
-15 - The script will launch Octane, render the first frame and save it, then close itself and reopen, render, and so on.
hope this will help.
edit : added step 10