panel probs - applets - how to get them back

[David Timms]

I get the following two error dialogs as the desktop completes loading 
after login:
1.
The panel encountered a problem while loading 
"OAFIID:GNOME_Panel_TrashApplet"
Do you want to delete the applet from your configuration?

2.
The panel encountered a problem while loading "OAFIID:GNOME_MixerApplet".
Do you want to delete the applet from your configuration?

I have been choosing Dont Delete, rather than delete; I'd like them back 
(vol icon and trash icon).

I expected first that there was some transient problem with devel, but 
now I expect that I've messed something up.

I think I need to re-install rpm -Uvh --force the appropriate package: 
but which package contains the things that these messages refer to ?

Perhaps others are seeing this ?

DaveT.