So I just found a solution to fix the problem. After looking in Firmware 2.1.7 API Document there is a command in there to clear the log data.
http://os-ip/dl?pw=xxx&day=all
where os-ip is the ip address of OpenSprinkler and xxx is your MD5 hashed password.
After entering the above url in the browser it returned the result {“result”:1} which apparently means success. After clearing the log in this manner the log data started showing up again in the gui. Of course the first time I looked at the log data in the gui it said that it could not find any data for this day (since I just deleted it) however I ran a valve for 30 seconds and then looked again and the data showed up.
Thanx a million @richardgedwards your solution has worked!