i had the same problem with exactly the same OS (8.1 64) and the same HP Printer that was installed before (Officejet Pro 8600).
So after deinstalling the old 8600 Pro, i can't install the new M477 software.
Error is the end of the install something with "webservices failed"... no clue. I even did hours long of support tickets and phone calls with HP Support a year back with exactly the same problem, no solution. (tried everything in the book) I ended up installing generic drivers.
This time i need!! the SCAN SOFTWARE. somehow the drivers are working for printing. But i need the SCAN Software so i can use the Scanner as it should be.
So, is there a STANDALONE SCAN SOFTWARE that i can install? Download from ftp somewhere? I am pretty sure this would work as it wouldn't try to install the whole software suite everytime... which fails. I don't need a solution to the install problem, a scan software would be 100% ok!