Squeeze/Sid + Gnome2 = security risk opening some kind of file

[Mirco Piccin <pictux@gmail.com>]

Hi all,
after upgrade from lenny/sid to sqeeze/sid, not all is working fine.
My actual problem is this: if i try to open some kind of file (i.e.
pdf, ods, png... ), happens that  a popup tells me:

"The filename "<file_name>.ods" indicates that this file is of type
"ods document". The contents of the file indicate that the file is of
type "OpenDocument Spreadsheet". If you open this file, the file might
present a security risk to your system.

Do not open the file unless you created the file yourself, or received
the file from a trusted source. To open the file, rename the file to
the correct extension for "OpenDocument Spreadsheet", then open the
file normally. Alternatively, use the Open With menu to choose a
specific application for the file. "

So, to open the file, i must right click -> open with -> choose the
right application.

Is there a way to solve that problem?
Thanks in advance!

Regards
M