There is no other code running, literally just printing hello world. The battery is fully charged and the errors occur at random, not at power-up. I am just leaving the AxonII on, and leaving it on for a while. I can't comment on frequency or amount of errors because I haven't counted them.
What I do see, is that scrolling through hyperterminal after maybe 5 minutes, I get some errors as I have described below.