Okay, done without the script ... finally got the unit to pull a dynamic IP address. Here is how:
1. First, reset Roku HD1000 to Initial Setup Mode as outlined here http://www.rokulabs.com/forums/viewtopic.php?t=9851
... that clears the old settings.
2. Then, reset/reboot Roku HD1000 using Standby button ... that acquires your homenet's particular IP subnet info.
In my previous attempts, step 2 did not work without doing step 1 first.
I still could use the script to set the static IP address on my unit ...