Double-click/drag & drop Photoshop files opens application but not file

Running OSX 10.4.8 on iMac G5, Photoshop 8.0 CS
Used to work perfectly before performing an Archive & Install to try to solve a shut-down problem (turned out to be power unit - now fixed). Have tried the solutions suggested at the top of the Mac forum for similar problem. Have reinstalled the software and copied the "Adobe Unit Types" from Previous System folder into Scripting Additions. This same software has also been installed on a MacBookPro and works fine.

Anyone any other suggestions to try to solve this?...

See this FAQ highlighted in big red letters at the top of the Mac Forum:

Scott Weichert, "Double-click/Drag-&-drop Photoshop files opens application but not file or I get a message saying that some files in Application Support are missing and I have to reinstall. (Photoshop CS/CS2)" #, 29 Dec 2003 1:45 pm </cgi-bin/webx?14>

I have. That's why I said in my message that I've "tried the solutions suggested at the top of the Mac forum for similar problem." That doesn't solve the issue in my case....

Archive and Install the system again

Have you shut-down and rebooted the computer since you copied the "Adobe Unit Types" from your Previous System folder into Scripting Additions?

You may need to re-install Photoshop from the original CD but remember to trash your original Prefs. before reinstalling.