Problem with formatting using content written with old edito

I am facing problem using content written using old editor. When I open the editor with the latest version, the layout goes haywire.

Here is how you can test.

Open the below mentioned URL.
http://www.aiacanada.com/extra/test.html

First scenario:
1. Copy the content from the browser.
2. Directly paste it on the demo version of the editor (2.6).
3. View source in the editor and then again change it back to the design mode.

You will notice that few content shifts at the bottom of the page. ("Solution de gestion environnementale" and "Normes de formation des usineurs en force motrice"). See the result in http://www.aiacanada.com/extra/test2.html

Second scenario:
1. Copy the content from the browser to dreamweaver (design mode)
2. Change the mode to "code" mode in dreamweaver.
3. Copy the code from dreamweaver and paste it in the editor in the source mode.
4. Change it to design mode in the editor.

It maintains the format.

I have also attached both the HTML files in test.zip.

I am facing this problem with lots of content. Can any one help me out with this?

Thanks.