Usually the release candidates of acr only support photoshop
and not photoshop elements (the installer anyway)
So my guess is you'll have to wait for the production release of 6.3
for photoshop elements 9. From what i hear, only pse9 will support the
6.3 final release.
If you need support for a new camera that is supported in 6.3, you could use
the 6.3 dng converter in the meantime.
For Elements you'll need to wait till the final release for the appropriate updater.
Can't the OP extract the 8bi file and install manually? Or am I opening a can of worms, and should keep my gob shut?
I actually am using CS5 and got the same error message when trying to install.
I second that - I am also using CS5 and am getting this same error message when trying to install ACR 6.3 beta.
Please try two things:
1. Download the ACR 6.3 again (can be a case of broken download)
2. Reinstall Photoshop CS5 in order to get a clean copy.
Please let me know if this helps.