You really don't want to back up proc, which is a "virtual" filesystem for the kernel.
You do want there to be a proc directory on your backup disk so add /proc to your exclude list and include a separate "mkdir proc" in your bckup script. BTW, cp isn't a waste of time since there is an update option for it so that it will only copy newer files. Remember that you can also use the "-n" option to test it out and see what happens without actually copying anything. Brian