Namespace prefix sodipodi for nodetypes on path is not defined

Hi there,

I'm trying to export a .SVG file from a .AI file. However, when I save it, I get the following error in the generated file: 

error on line 46 at column 103: Namespace prefix sodipodi for nodetypes on path is not defined.

I am trying this all my other ai files and now they are giving the same problem that never do before.

how can solve this problem