If a patron asks you about error code 80040812, the message the patron received should have read:
"Failed call to fulfill the title - the fulfillment limit for requested title has been reached"
It simply means they've had their three downloads, and that they will need the downloads reset. Each library should be able to do this by logging in to Content Reserve and looking down towards the end of the reports list for the reset downloads report. You will need the title.