Hi Joe,
At the point in the script where it failed, FocusMax is controlling the operation, not ACP. FocusMax gave up - because you have the maximum exposure set to 5 seconds and the required exposure was predicted to be way more than that. The real question is why was a 72. mag star was apparently so dim (only 4000 adu). I would try again, a couple times in different parts of the sky, to see whether there is a consistent failure. Could just have been a one-off event. I don't think using the Acquire Star Feature will change things. Good luck.
I don't know if your operating remotely, but FocusMax does show the position of the focus star on the imaging chip (upper left-hand box, I think). You wouldn't see that if you're remoting in.