unable to import from Illustrator

Hi !
As I said in the title, I've met problems to import an .ai file, but let me say straight that it's not because of the "Use compression" checkbox checked ! Here are the facts :

- Working at home, on Illustrator and AE CS3, it was OK, I made my .ai file, unchecked the "Use Compression" option, and imported it without harm into AE.
- Then I go to finish the job by the company. There I work with Illustrator CS2, and AE CS4.
> I could open the .ai file I made at home ;
> There was no way to open an .ai file made there (with Illustrator CS2). No way. And of course I unchecked the "Use Compression" option.

Do you have an idea about how to fix the problem (for the next time) ?

Thanks,