You will have to check the list of supported cameras in the Lightroom or the ACR readme file. If your camera is not listed, then it is not yet supported. And trying the DNG Converter isn't going to help because it supports the same cameras. I don't know anything about the camera that you mentioned. But you indicated that you just tried it. That suggests to me that it is a new model. If that is the case, it probably was introduced after the ACR/Lightroom additions were made for this update. And if that is the case then you will have to wait for about three months for an update. In the meantime, get to know the camera. And you can open your JPEGs in Lightroom or ACR.
… Just tried the DMC G2 and the raw file format was changed to RW2, which ACR 5.0 cannot open. I then tried DNG Converter 18.104.22.168, which also fails to open RW2 images.…
That camera model is not supported yet.
ACR 6/3 was just released yesterday, so you will have to wait at least until mid March, 2011 for the next release, which may or may not support your camera.
You'll have to use the camera manufacturer's software.
Wo Tai Lao Le
The raw files from the Panasonic DMC G2 with a suffix of ".RAW" are in the list of supported cameras. The files with that same camera with a suffix of RW2 are not listed as supported.
You specifically mentioned that "the format has changed to RW2." That's a different animal.
Wo Tai Lao Le