I also see that ipconfig is reporting the suffix domain name:

$fhname="@hostname"
?"Full Host Name= "$fhname
$shname=Substr($fhname,1,$nlet)
?"short host name= "$shname

Full Host Name= CALLA
short host name=
C:\Temp>ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : ucdavis.edu.
IP Address. . . . . . . . . . . . : etc..

Not sure what is missing for XP not to send back the full name as CALLA.ucdavis.edu???