[users] Filter selection problem

[patrick and mary]

I have been using openoffice for about 3 years and like it, but,
now when I try to open any of my calc (spreadsheet) files, it asks me for:
"Filter Selection" and it gives a list of a bunch of file types.
I have tried almost all of the possible types and nothing works.
I have Open Office 2.1 installed.
Help please.
Thanks