It is a fairly important part for retaining the versions of the pages you are creating. Without this timestamp in this field you will have trouble checking the history of a page and reverting back to it. Does your GUI tool allow you to edit the table like this? If you are using phpmyadmin you should be able to alter the table by adding in the default value for this column. The version of MySQL that you are using may be part of the problem but I was not able to confirm this in my searching.