You can find help with that error on Apple's support site. I can't say for sure, but 'attaching' your iPod to the computer using Scanners and Cameras may have left it in a mode that prevents iTunes from properly accessing the device. To my knowledge, iTunes software is the only officially supported means of connecting and syncing content between a computer and an iPod touch or iPhone. I don't believe the use of the Scanners and Cameras feature of Windows with an iPod touch or iPhone is supported by Apple, based on this Apple support article.