If you are near the end of your fiscal year and want to create a post-dated check, you must post to a future year.
To do so, make sure the Create GL Transactions By option is set to Creating a New Batch on the A/P G/L Integration screen.
If Create GL Transactions By option is set to Creating and Posting a New Batch, the system tries to post to the current fiscal year, not a future one, and an error message appears.