Missing all file types

[Pedro Gauna]

Hi,
 I'm new to the list (I came from ubuntu-es, they can't help me)

I have Hoary, working fine, but I have a problem very hard to resolve. I 
lost the gnome's file types. When open nautilus and navigate to a 
folder, ie: with images (png,gif,jpg,etc...) nautilus put in file type: 
program and don't show the thumbnail, and when i double-click the file, 
its tell me can't open the file
It happens with all kind of files (.avi,openoffice,tar.gz,etc)
If I open the file properties and select "Custom icon", open a window 
(usually full of icons) empty!, no icons!

Some help?

Thanx in advance, and don't laugth a lot about my bad english...

Pedro