Yes, it does look like there is a problem with the history log. Issues with that log are very rare, so I have to suspect a problem with the SDcard. If the card is very old, or if the card has these markings, it should be replaced.
When doing so, do not copy the /iotawatt/histlog.log file. You might also delete the iotamsg.txt file as it is probably filled with these restart messages.