Here's my fix for the issue with shared wallets I discovered earlier:
https://github.com/mikaelh2/primecoin/commit/a1c3f5854e9970d2f9f13ff75601dc7c87bf83c3

Basically this should help people who are running lots of miners using the same shared wallet. My fix is to initialize the extra nonce value using the current value of a nanosecond-precision clock. That should give a unique value on every machine. Boost.Chrono is now required for compiling and I have updated the makefiles to reflect that.