The key files need to be in OpenSSH's format.
For example the pubkey file should look like this:
ssh-rsa AAAAB3NzaC1yc2EAAAABJQAAAIEAo6uBphcbl
5iS7U0fjE1ZJ8ZPqYwezFbxyN13YYucrFDCbln9Q6S33lN
JMYKUY4711qzDOxQD0bratDQfHUl4waT35qI+NRQa2
B+UWHYaOhbt5FI0Ks7JXPxj3iJ/+joiKQW3Bj8eH8Nzg
sTx4tEVPD6QOHs682OhUNX6sqSnHA8= rsa-key-20060606