Bryce,Hmmm.. Hmmm... Hmmm..
I just tried it here and works great for querying a machine across to another domain. Are both of these Domain controlled by 2000 PDCs? And I am going to assume that you are a Domain Admin on Both Domains and you have Administrative Access to the box you are querying and the one that you are initiating the query from.. 
I made some tweaks with your code, but should be the same..
code:
break on cls$OtherDomain = "Garts"
$AdminID = "bryce"
$AdminPass = "<password>"
$WkstatoQuery = "brycetest"
use "\\$OtherDomain\ipc$$" /user:'$OtherDomain\$AdminID' /password:$AdminPass
$group = GetObject("WinNT://$OtherDomain/$WkstatoQuery/administrators")
? "@error:@serror"
for each $member in $group.members
? $member.name
? "@error:@serror"
next
use "\\$WkstatoQuery\ipc$$" /d
Thanks!
- Kent