Inviting people to be authors on your blog

I have invited the following people:

njellevsen@gmail.com
saracabreramultimedia@gmail.com 
Harvey.rancudo@gmail.com

gary.lom@gmail.com
hi340@hotmail.co.uk
njellevsen@gmail.com

• My Invitations have been accepted by Harvey, Sara & Gary.
• But I had access only to Harvey's blogs and I have commented on 2 posts.
• Sara's posts seem to be locked.