Appleworks USB Incompatibility
Appleworks and 10.6.8 was working with USB before, then stopped working, correct? 

These are the trouble-shooting steps I'd go through for your USB problems: 
-- Try backing up and deleting the Appleworks preferences file 
-- Try a different USB Port 
-- Remove USB devices one by one to see of one device is the problem.  -- Try a different USB "string" (cable? / thumb drive?)  
-- Repair Disk Permissions  - http://support.apple.com/kb/HT1452 
-- Reset PRAM - http://support.apple.com/kb/PH6478 
-- Update or Reinstall Appleworks