Downloading trial version of Master Collection CS5.5 'Illegal Seek'??

After the download of the Master Collection of CS5.5 and than waiting for it to affix I got this message on the Adobe Download Assistant 'The setup file cannot be located (error 103).  Navigate to the folder where you downloaded the product, and start the installation manually'.  I than went to the folder on my desktop clicked on 'Master Collection_CS5_5_LS1.dmg' and a warning box came up that said 'The following disk image couldn't be opened' with the reason being 'illegal seek'.  What is this?

The only thing I can think of is that I downloaded the Master Collection about two weeks ago, found I didn't have a current enough operating system, so I tossed the collection.  Figuring once I updated my operating system I could re-download it.