@Rob: other similar coins' wallets have the handy "-resync" flag for this process; would it be possible to implement this into the BBP wallet?
What is resync? Do you mean -rescan or -reindex ? options are available as tools under wallet repair.
I'd try a reindex before you blow everything away except wallet.dat in your biblepaycore folder.
Also, is everyone using addnode=node.biblepay.org in their biblepay.conf ?