I upgraded to 8c as it contained some fixes for my box not always finding the IDE HD (timeout probs).
I now occasionally get the sync failure errors.
However, my solution to sorting this is:
Drop to the shell in the developer version, unmount /drive0 & /drive1 (is present) and then run fsck.ext2 on them.
Restart the player and then get Emplode to syncronize again (usually watching on the TTY session to the box)
So far this has solved the problem every time it has occurred.