You must receive an invitation to become an author on this blog if you wish to create new posts as opposed to simply commenting.
To anyone who has contacted me about joining the Art-a-Day challenge I have (hopefully) sent you that invitation. Connect to the blog from that email and it ought to then recognize you as an author. If I missed you on the invitation list - sorry! If didn't receive it or would like to have it again, please send me a note with the email address you use for your google account and I'll send or re-send the invitation.
I had all kinds of challenges when I first linked in - including it transcribing my writing into some other language! - so I understand how frustrating it can be.