I upgraded to 1.1.6.4 and get the message 'Checkpoint is too old. Wait for block chain to download or notify developers'
Is that normal behaviour?
Did the whole blockchain download? If not, let it download and if the warning is still there, do the following:
Close your client and go to your AppData/Roaming/CryptogenicBullion folder.
Delete blk0001.dat, blkindex.dat, and peers.dat in your data folder.
Do not touch the wallet.dat file or else you'll lose your coins.Then restart the client and you should see the client downloading the blockchain.
Sometimes, for whatever reason, the client won't cleanly download the checkpoint data, so that's why you're seeing the warning.
I have downloaded the entire blockchain 3 times now (after deleting the files you indicate, and also trying deleting all but the wallet.dat). I still get the 'checkpoint too old..' message.. Using client 1.1.6.4 of course.