I found the quote below with a Google search. It confirms your observation that the files won't open in Photoshop. As you probably don't have the HP software he suggests, try downloading Irfanview. Irfanview will likely be able to open the files and you can then save as a TIFF and try again in Photoshop.
>>>The TIFF files the 8000G produces are a bit 'quirky' in that Photoshop CS does not open them. I have only found out a solution to this problem since my last diving trip.