Keynote on Lion painfully slow at loading files

Hi everyone.

I have been searching through forum and communities for a long time, but I could not find any proper method to track down, nor fix, the cause of the unbearable load times of Keynote on Mac OS X Lion.

In order to make everything clear, I'll give you some technical details first.

- Late 2007 white Macbook with 4 GB of RAM. 2,2 GHz Core 2 Duo CPU.

- Mac OS X Lion v10.7.5, fully updated (but I can remember the problem with every version of Lion)

- iWork '09, Fully updated

- The problem: Keynote is painfully slow at loading presentations

More detailed information:

Even with small presentations (less than 10 MB), Keynote makes my system unusable: 3 minutes and 30 seconds to open a 6,9 MB presentation.

The spinning beachball appears ONLY if I move the mouse cursor over the Menù bar. Fans sound like they have to cool down the ****.

Once the file has been loaded, Keynote works smoothly.

I have tried to disable file versioning, create another presentation with the same contents.. but none of those tricks worked.

The only thing I could not try is the installation of the 9.0.5 version of iWorks '09 (because I don't have it).

I really hope some of you could help me with this.

Thanks in advance,

Maurizio