Open Office ASCII Filter Options  

I am currently using a Linux (Xandros 4 to be exact) laptop for much of my writing. It runs Open Office 2.3, which has generally worked quite well.
However, I saved a file recently, and when I opened it again later a window opened up asking for which ASCII language I wanted it in. I had saved this as a regular Open Office file, I didn't choose anything different. Now with whatever language I open it in, I just get a 162 page long document filled with symbols, mainly #'s.
This is a relatively important document, as it contains all my notes for other documents. I have already had to rewrite it once due to this same thing happening and do not want to again.
I also fear that a similar thing will happen to more of my documents, some of which I have put more than 200 hours of work into.
Is there any way to retrieve this document? Is there any way to stop this from happening again?