OK, I've just fixed this a few minutes ago. Bit of a nightmare... really. Who ever wrote this should be shot. No idea if this will help you, but well.. I hope so.
I'd been mucking with a new install, and had just moved around drive mappings - used to have a G:drive and now no more.
When trying to install it would fail on CCC and the transcoder piece
In event viewer -> windows logs -> application there was a nice fat error saying
"Product: AMD Accelerated Video Transcoding -- Error 1327.Invalid Drive: G:\"
Went to regedit, searched for "G:\" and found four links to docs, photos, videos and music. Pretty innocuous. Anyway I manually changed all four to point to my E:\ drive, where I keep that stuff now. Closed regedit, ran install - went through straight away.
Hope it helps.