[Hernan Torrisi]

ok try the second option.
select the path in illustrator. Choose Object>Path>Outline Stroke
Then copy the path and paste it in the position layer of your object after having created a keyframe.
It should work fine like this.

[Hernan Torrisi]

I think i had a similar problem. You should use the Pen tool to draw your paths. When I used the paintbrush tool, i solved it selecting the path, choose object>path>outline stroke. It worked but the position duplicated and i had to erase one of them.

Hope it helps