Disk Images: - 50 Error Message

When I double-click on a disk image file I downloaded, I get a message that the disk could not be mounted because for a -50 error.
You have a version of Disk Image Mounter previous to 2.1 on your hard disk, which cannot read disk image files created by Disk Copy 6.1 or later. You can drag the disk image file directly on top of Disk Copy and it will mount. Removing all versions of Disk Image Mounter, installing Disk Copy 6.1 or later, and rebuilding the Desktop will resolve the issue.
Published Date: Feb 18, 2012