After downloading I cannot complete the update - message "The operation can’t be completed because you don’t have permission to access some of the items."

Using Version 1.0.0 - beta build #1:396 - "Beta Version - expires Mar 13, 2009"

Operating System
Mac OS X i386 10.6
Java Version
Apple Inc. 1.6.0_15
SWT Version
3448
Memory
62MB total, 50MB free, 508MB max