panel encountered a problem

[Bob Wooden]

I have successfully built a newer Edubuntu server.  When users perform 
their initial login, we are getting four (4) error messages. 

The first messages states: "The panel encountered a problem while 
loading "OAFIID:GNOME_Panel_TrashApplet"."  The second message is 
similar but is for "Deskbar_Applet."  The third is for 
"GNOME_FasrUserSwitchApplet."  and the last is for "GNOME_MixerApplet."

These four items are missing from the desktop, and yet the client 
appears to work fine.

How important are these applets and are there absence effecting the 
desktop function?