Uploading photos "camera Error"

Did you instal the drivers

Try NOT connecting your camera to your computer.

The best way to transfer pictures from your camera to your computer involves removing the memory card from the camera and plugging it into a card reader (either built-in to the computer or connected via USB). This is likely to be faster than connecting the camera to the computer, and won't run down your camera's batteries.

Once the card is plugged in, it will appear to your computer as a removable drive. You can use the operating system's drag&drop facility to copy pictures from the card to the computer's hard drive, the same way you copy any other files. Or you can use any photo management program such as Picasa.
Organize edit and share your photos

Your memory card probably got some files corrupted. You need to reformat it. But you will lose all the pictures.

Try NOT connecting your camera to your computer.

The best way to download pictures from your camera to your computer involves removing the memory card from the camera and plugging it into a card reader (either built-in to the computer or connected via USB). This is likely to be faster than connecting the camera to the computer, and won't run down your camera's batteries.

Once the card is plugged in, it will appear to your computer as a removable drive. You can use the operating system's drag&drop facility to copy pictures from the card to the computer's hard drive, the same way you copy any other files. Or you can use any photo management program such as Picasa.
Organize edit and share your photos

Consider NOT connecting your camera to your computer.

The best way to download pictures from your camera to your computer involves removing the memory card from the camera and plugging it into a card reader (either built-in to the computer or connected via USB or FireWire). This is likely to be faster than connecting the camera to the computer, and won't run down your camera's batteries.

Once the card is plugged in, it will appear to your computer as a removable drive. You can use the operating system's drag&drop facility to copy pictures from the card to the computer's hard drive, the same way you copy any other files. Or you can use any photo cataloging program.

This is why the pros always use a card reader instead of the camera. When you disconnected the camera, did you remember to use the "safely remove hardware" function? The computer was obviously still trying to write and communicate with the camera and if you just disconnected it, the camera became corrupted. Check your manual for instructions for a camera reset. Try that. Also, remove the card and batteries, press every button, leave it alone for 20 minutes, insert the card and then the batteries, turn it on. Sometimes this works.

http://www.usa.canon.com/cusa/support/consumer/digital_cameras/powershot_sd_series/powershot_sd780_is#ServiceAndSupport

Troubleshooting the camera displaying Communication Error when connected to the computer via USB. If the camera displays "Communication Error," when trying to download images the main cause for this error is that there are more than 1000 images stored on the memory card. It is recommended if there are more than 1000 images on the memory card, that you use a card reader to acquire the images, or to delete images off of the memory so that there are less than 1000 images to download from the memory card.
If this is not the case, there are not 1000 or more images on the memory card, try reconnecting the camera to abnother port on the computer, try another cable or another computer. This error can also display when connecting to a direct print printer. Please check with the printer manufacturer for more information on this error.

Use a card reader instead of your camera.

Try using a card reader or reinstall the camera software. Let me know how it goes.

you need the driver for your camera so that the computer can read