E620 problems downloading to computer

For sometime now when I connect the E-620 camera to either a Mac or PC to transfer photos I get the message "no connection" on the camera screen. On the Mac it does not show up on the computer screen nor can I find it using disk utility or olympus master. However, Aperture can pull the photos. On the PC it can not be found other then by going to "my computer" where it will show as a hard drive and I can open it and drag and drop the file to copy. Any ideas? no firmware updates at the olympus site for the camera and olympus master is UTD. Thanks