problems while importing svg format to synfg

I using ubuntu 12.04 lts, and installed synfing 0.64.1, my inkscape is 0.48.
When i import svg to synfig, the vector files come with alot of problems.
I installed the plugin svg2sif into the inskape but when i close and start inkscape, i dont see nothing about the plugin.
i saw this tutorial video step by step in youtube:

is very important to import vector files without problems
there is a lots of jobs for disigner and animators to animate vector files, like:
logos from some company or other stuff in vector file.

Hi sergio,

Can you double check that you have all the needed files in the proper folder? … /