I have found a simple solution : download and use DNG Converter 7.3
FYI, I'm running AE CS6 and LR5 and I get the same error. Everything is up to date. Adobe just doesn't care. DNG converter is fine for the odd conversion, but when dealing with literally hundreds of thousands of images, it's a huge time suck. Almost as big a time suck as Adobe is an everything suck.
You can always batch convert in LR or PS.
Not trying to dismiss your all too valid criticism, but who knows what happened to your files, what metadata they may contain and so on.... There's a million things that could lead to inconsistencies even in a sequence shot on the same day...
Thanks for the feedback. I do appreciate it. And based on it I've just done a few little tests:
Shot 10 RW2 stills on a freshly formatted SanDisk Extreme card inside my GH3. Put the card in the reader and imported into Lightroom. Closed LR. Opened AE. Tried import. Failed.
Next, I copied the RW2 files to a folder (skipping LR import) and tried bringing into AE. Failed.
Then I pulled out my old GH2. Put the card in it and it could read the RW2 files from the GH3 without any problem.
I then shot another 10 RW2 shots, this time on the GH2. These AE would import as a sequence (after an OS copy from card to HD, I didn't bother passing them through LR).
Now it could be Panasonic has done something funky, in which case bad on them. But then the GH2 can read the GH3's images without a glitch so I'd bet against that.
Although Adobe claims to fully support the GH3, they clearly don't. Support in some applications but not others does not equal support.
Ok, so perhaps this is the problem. I can't believe Adobe's incompetence... or is it negligence?
Adobe supports the GH3 in ACR 7.3 but not earlier (http://helpx.adobe.com/creative-suite/kb/camera-raw-plug-supported-cameras.html).
Little did I realize that installing ACR 7.3 doesn't actually update the software across all applications. Nope. Looks like AE is still stuck at 7.1. In fact, this table (http://helpx.adobe.com/creative-suite/kb/camera-raw-plug-supported-cameras.html) shows what an utter and complete mess Adobe has made of ACR.
So Adobe IS the culprit here. A bit more digging and I see they released ACR 8.1 so I'm doing that update, but from what I've been able to find online, it only updates PS.
REALLY FRUSTRATING ADOBE!!!!