Dont know if this will help..I am on same system, all I have to do is turn on the camera, connect it to computer via usb cable and instantly the folder iwth my new pix shows on desktop, I drag them to my Desktop to copy them....maybe THEN you can get them into iphoto...
I had a similar problem with my Sony DSC-T1. Sony had a firmware upgrade that solved it.
If that doesn't work. Check the application "Image Capture". You normally won't know it's there or loaded. This is the software that the Mac uses to recognise your camera when attached and then opens iPhoto for you. If the preferences have changed it my not be either looking for a camera or opening iPhoto.
Have you tried using a USB memory card reader?
I don't know if this'll help but click on the Desktop, not on a file or folder, then hit the command "⌘" and "," keys (without the quotes) or Finder > Preferences > General tab, choose Hard disks to show on the Desktop.