First off, to let you know in my five years of NT administration I NEVER had this problem...so I'm shooting on instinct here...
My guess is you some how have corrupted SIDs maybe...the SIDs uniquely ID each PDC, BDC etc. if this is the case the only safe way to restructure them is to re-install the NOS.
It obviously doesn't know your PDC is really a PDC - otherwise it'd play great with the BDC..this is why I theorize about the SID's.
However, have you tried tricking it to get the correct BDC and PDC recognized? Take the "PDC" offline totally, turn it off. Using Server Manager promote the BDC to PDC, now when you boot the ORIGINAL PDC (which up until know was offline), you'll be prompted with an error message (because you can't have two PDC's in a single domain), this is when you'll have the option to DEMOTE one to a BDC. Do this, thus setting up the correct PDC and BDC configs you want. When its done - synchronize them both to update the user accounts. There's no reason it should be giving you the IP address conflict - that is assuming that you have *UNIQUE* static addresses (of course you know that each machine needs a UNIQUE and static address, right?). No BDC or PDC should ever use a dynamic IP assignment. If you need more help, email me I'd love to help solve your problem.
Take care.
Tom
