I did update the print server machine to Ubuntu Gutsy, which has a
kernel with working LDUSB, so gotemp-ldusb.py works fine.
However, I just did a simple icebath test, and it reads no lower than
0.72C...
I got email from someone who's in touch with the vendor; it turns out that they have an SDK and that there's a calibration step that one should use when talking to the hardware, but which isn't documented anywhere else. Some poking around points to http://www.vernier.com/diy/ which is mostly about the LabPro products, but there are some Go! drivers there that I should clearly take a look at.