It could be a number of issues. But, if you've been editing with video from this camcorder before and you're suddenly not able to, it's likely a codec was damaged.
One way to repair the codec would be to install a codec pack like the K-Lite Codec Pack, available here:
The chances are great that your new computer does not have the same CODEC's, that your old one did.
I'd recommend G-Spot to determine the necessary CODEC's and then to Google for them, and install them. I am a big believer in not just installing CODEC's, because they are available, but only when needed. I also believe in going to the source for my CODEC's, and not going with the same (or seemingly) "free" CODEC. I want to go to the source.
I'm really getting frustrated with Adobe. Premiere elements is great when it works, but it seems to create so many problems and slow down my computer so much (I've tried 3 different computers with the same result every time!) that I am seriously switching to a MAC for my video / picture editing.
I downloaded Gspot and checked the files I am having trouble with (standard MPEG-2's) and I have the codec's installed - They play fine with Windows Media Player. And now all of a sudden they work with Elements again. Way too frustrating.
Adobe better do somehting to make this run smoother and quicker.