[MacGroup] shortcut keys

[tom holloman]

HELP.  I have a G4 Powerbook that does not behave properly with  
shortcut keys.   In preferences-keyboard/mouse -shortcut keys, I have  
checked the F9 key to show all windows.  When I click the F9 I get  
something that looks like a volume control.  Any ideas on fixing this?
PS-I have 3 Intel based iMacs and this feature works perfectly on them.
Thanks for any suggestions:
Tom