Sorted! (Sort of...)
Still all sorts of errors on my twin-cpu box running NT4, but success on an old PPro box, except that synchronisation fails at the very end every time - possibly because I'm running MSIE older than 5, I dunno.
(the twin box can get between one and three tracks on before bombing out, but the database stays intact, which is nice :)
Getting there! If you want detailed debug from the twin box, let me know. (This is using Ethernet. USB from a win2000 box went fine, but USB is a pain in the arse)

Steve