A time ago I did have tried to import my secret key to my ArchLinux system but I
can't. Tried to use --import and --allow-secret-key-import too but both
don't work. I was using my system only console mode, without X server.
A while later I needed install X server and remembered to try import the secret
key. And, works!
So, the problem is: GPG use a graphical window to user insert his passprhase.
When use only console mode (a user that have old customs or in a server) this
window can't appear and GPG doesn't import a secret key.
Possible solution: change the graphical window for a cursos like passwd.