Panel apps quitting unexpectedly

[Florence Berbain]

Hi,

When the Gnome desktop starts, I get the following error from the bottom 
panel:

<error message>
"Show Desktop" has quit unexpectedly
If you reload a panel object, it will automatically be added back to the 
panel
</error message>

This happens for all applications in the bottom panel. If I choose to 
reload the object, it's usually fine, but not always. Sometimes the same 
error happens again.

This has been happening for about a week now. I don't remember fiddling 
with anything recently (but then of course I could be wrong). Does 
anybody have an idea what the problem is?

This also made me realize that I don't know how to access the window 
list in Gnome (other than by clicking the Window List panel app).  How 
do I do that?

Thanks for any suggestion,
Florence