It's a long time ago for me, but how can the filer find his domain controller without wins with a NT4 domain? I suppose that the domaincontroller is not on the same subnet as the filer, so I think you need wins in a NT4 configuration. If he don't need wins, check on the filer site if you can reach the dc by pinging poly.com.
Make sure the filer's time is no more than 5mins off from the DC. Even though the time make look like it is in sync, make sure you have selected the correct time zone as that will throw the time sync out of whack.
Hope that helps. Shout back if you're still having issues.
If you're truly joining an NT4 domain, the time shouldn't matter. That's a kerberos thing that came into play with AD.
With NT4, you've got to worry about a couple things:
1. Your PDC (not a BDC) must either be on the local subnet so it can be found via broadcast or, more preferably, via WINS.
2. You must create the computer account manually. cifs setup will not do it for you, like it can wtih AD. If the account already exist, you must delete it and re-create it so it has no computer account password. One will be assigned when the filer connects.