Should have posted about this earlier. I have been updating the Sanguino project over on Google Code with the changes I have made to support the atmega1284P and support up to arduino 0023. If you have issues with the HEX files I posted here earlier check out the new versions. If you still have problems open an issue on google code, I try to go through the issues reported ever week or two.
[...] (details): Sanguino-0023r2.zip UPDATED (details): Sanguino-0023r3.zip [...]