JPEG to DNG in Lightroom: can't open the DNGs

Question

Hello,
I've been importing images into Lightroom, and have had good success saving DNGs from my Nikon D2x's NEF files, and opening them back up in CS2 to verify their ability to open and become a good archival file (upon learning of the glory of DNG for archival purposes from Seth Resnick and Jamie Spritzer at this month's D-65 workshop in Denver).
My problem: A good portion of my earlier work (shot on D100, D70 and D2X cameras) was captured as JPEG. I have imported some of these into Lightroom and likewise attempted to make DNGs from them in order to optimize them for long-term archiving. However, when I try opening these DNGs in CS2, the dialog "Could not complete your request because Photoshop does not recognize this type of file" appears, and they will not open.
I will be shooting all RAW from this point on, and so the problem isn't with my NEF files from here on out. But will I always be unable to make a readable DNG from these older JPEG files, and thus should I archive them as TIFFs instead? I tried using the Adobe DNG converter, but it still didn't create a readable DNG file out of a JPEG, and I'm not sure that anything will.
I do not wish to rely on these JPEGs to stand the test of time (after seeing many become corrupt through the years), so I'm looking to change them to something else. Any suggestions for a good alternative archival file format for JPEGs, or methods of making them into readable DNGs?
Thanks,
Greg Latza
Sioux Falls, SD
http://www.peoplescapes.com

Answer 1

Jeff, Fred and John,
Thanks for the input...I did update to the proper ACR and was able to open the DNGs; I had forgotten that I'd updated it on my laptop but not this desktop G5. So now it works, and thank you for the tip.
I do agree that JPEGs are going to be very relevant for a long time, but it seems like I see a lot more corrupt JPEG files over time than other file formats; I'm trying to find a format that will be more reliable over the long haul, and less apt to have problems (lines through the file, blocks, etc). Would the DNG format be more reliable in this way?
Since I'm importing these older JPEGs into Lightroom from an archival standpoint, catching myself up to the present with my image database, I'm also trying to makes DNG folders of these files at the same time in order to archive them, and thus not have to return to the files again for this purpose (tip from the D-65 workshop).
Thanks again!
Greg