Try to export as json, blender throws this error: AttributeErrpr: 'Image' object has no attribute 'file_path_from_user' Hey guys, 
I recently started working with blender for a game which will be programmed in three.js. Therefore I export my model as a json file. As I load textures from png files in it, blender throws an error pictured in the photo.
Thanks for every advice!
You need to update your version of blender. The image.filepath_from_user() was added to blender in 2.70 and you are using 2.69

This answer appears to include an up to date source for blender.

If you are using steam you can also install blender from there.