Sounds like the problem might just be those few workstations rather than your scripts/servers. Try to nail down if it's always the same machines that freak-out on you.. if you are able to establish that only those few work inconsistantly... well..
then either start troubleshooting those systems (look at shared dll files, startup-programs etc) or simply re-load one of them from scratch and wait and see if it fails again. If the one that was reloaded doesn't fail again, then you know you've got to repair the others. Also you might have strange network settings in those computers..
(WINS for instance, if it was set incorrectly it might confuse the machines when they try and resolve the servername of the server running KixRPC)

Good luck..