maximum number of characters in page

Hi all,

I’m facing a wall with this and I’d like to see if some of you have any idea of how I could solve this issue.
One of my client has this website using WP 3.3.2 using Broadscope theme. I don’t upgrade it because he is using many plugins and, since I didn’t installed the whole stuff, I prefer to not mess up everything.
He is trying to update a page with a text that is 1600 words long. The problem is that every time we try to do a change on this page, our changes are not saved, even though WP says that the page has been edited.
I was able to delete some content, and to re-add a paragraph or so, but I can’t add anymore text to this page.
I’ve tried to deactivate all the plugins and active the Twenty Eleven theme but even in this really basic configuration this doesn’t change anything.

So my question is: is there a maximum number of words / characters we can use in a page? Since the field in the database is a text field, I don’t understand why this would be the case, but eh, perhaps WP has some limitations I’m not aware of.
The other question is: what could cause WP to prevent us to add more text to this page?

I stay available if you need more information.

Thanks a lot for your help.
Romain