Moving this discussion to the Photoshop Elements forum.
this is the link for supported RAW formats
1. check which version of ACR is installed with your PSE
To check follow this :
Windows : Open Elements Editor from the welcome screen, then goto Help >> About Plugin >> Camer raw
Mac : Open Elements Editor , then goto Photoshop Elements menu>> About Plugin >> Camera raw and check the version
Check the version there, if its less that 6.5, then you have to update because the camers that you are usning , it requires 6.5 ACR version to work with PSE 10
To update goto Elements editor and and then goto help and update and this will show up the available updates for you PSE 10 which will include ACR as well, once the update is done and installed , then relaunch the PSE 10 editor and then check the version once again to be sure .
If it has updated to 6.5 or later then check your RAW files, they should work now..