canon sure shot 85 "blinking H" question

I lost my manual and don't know why my camera sometimes has a blinking "H" in the picture counter window. When this happens it won't take a picture. It usually happens when the weather is hot. Thanks for your help!

Hi

A blinking H indicates a problem with the auto rewind caused by a low battery. Turn the camera on. If the H is still displayed, replace the battery.