Invites plugin - import feature

Hello

I tried Invites plugin which seems to be great to allow users importing contacts from Hotmail, Msn, etc.

When I click Import Contacts it says the service is not available.

Do I need something special to get it available ? In the source code I've seen a line $invite_incsub_authcode which is empty.

Should I contact Incsub to get this code ?

Thanks !

Gautier