When moving .slf files to the server, you need to preserve the original file exactly. Any changes, even a space in the file can cause issues.
There's a hash of the file contents in the file. If the .slf file contents change at all, it will not match the hash, which will make the license import fail.
A good way to preserve the original .slf file is to zip the license files, then move the .zip to the server and extract to a local directory. Then you should be able to start the v10 install and browse to the .slf file.