You should review your camera manual. Here's a link
First, the "Auto ISO" message is simply informing you that the ISO value (which is the sensitivity to light - the same as film ISO values. The lower the number the less sensitive and longer the exposure needs to be. High ISO values are more sensitive and require less time - but become grainier as the value increases) is not set to any particular value, but will adjust up and down as needed. ISO is mentioned throughout the manual, but begins on page 53.
The "r09" message is letting you know that the internal memory buffer has enough room for 9 images to be taken in rapid succession - before the camera must stop shooting to transfer those images from the buffer to the removable memory card. If you held the shutter release button in continuous shooting mode, the "r09" would decrease by one after each exposure until after "r01" was taken. then the camera would not shoot until the buffer was transferred. page 55 of the manual details this indicator.
It is important to note that neither of these conditions is an error message. Also, neither would prevent taking a picture. What can prevent an exposure is an out of focus condition. The focus is set to either Manual Focus or Auto Focus in the quick settings display and on many Nikon lenses made for use with digital cameras attached directly to the camera. Page 61 of the manual describes this in greater detail. Make sure that the the camera settings are not conflicting with the settings on the lens (if equipped with the M-A or M/A-M switch like the one shown below).
If you set the camera and lens to manual focus, you can release the shutter at any time - regardless if the subject is in focus or not. If in Auto mode, there needs to be sufficient light for the camera to focus. If the lens does not attempt to focus, the focus motor could be having a problem. The D60 does not have a focus motor in the camera body like most of the other Nikon cameras, and must use lenses with focus motors built into the lens instead. Use of a lens that does not have a motor will have to be focused manually. Only AF-S and AF-I designated lenses can auto focus with the D60 camera body as indicated on the bottom of page 18. Compatible lenses are listed on page 181.
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