Select Firm Settings from the Start Up menu. Check the Month Last Cleared field. It should be set to the number of the last month you were posting in. For example, if you are currently doing the majority of your posting in August, the Month Last Cleared field should be 7.
This message is intended as a warning to prevent accidental postings into the wrong month. If you want to post with the date you have entered even though it is not within the current month, click OK to this message and proceed.