When this error is given, it usually means that the Starting week in the Pool Settings has already started (pick deadline passed and games in progress or over).
No problem! You can check this by going to Commissioner Console --> Pool Settings --> Pick and Scoring Settings.
From there you can determine if the Week is correct, if it is the current/past week update it to the correct start week.
If all else fails, hit that support button and we are happy to assist!