Problems with "Hugs for Windows"

I have students using Hugs for Windows, Version: December 2001. Unfortunately, string handling appears to be somewhat erratic. I have attached one example. If this program is loaded and the following expression evaluated a number of times, each evaluation gives a different (usually wrong) result. dose (p,x) i Everything works correctly with the command-line version of HUGS. Thank you for your time. David Gray