I'm trying to upload a photo and see the following message:
"You already submitted this post! You might have accidently double clicked, or tried to refresh."
This is nonsense. I can not even put a post under rookie. Although what I'm rookie?
I get that one from time to time; it happens if you've submitted a post but then changed your mind and press the 'Back' arrow. Then you change your text and press 'Post' again but it won't let you. The only thing you can do is let your post stand, go right off the site, come back on then modify your post to what you really wanted to write or adding the photo you meant to add in the first place..
Can't imagine why it won't let you post in the Rookies. There are no blocks on your account (within the constraints of being a Rookie) so you should be able to post replies anywhere that Rookies are allowed to.
Like all Websites you're new to this one will take a little getting used to as it has its own peculiarities, but it generally works extremely well and with a couple of days practice I'm sure you'll be cruising around it!