Hi Rich,
I just happened to be reading it could have been anyone.
I have just been to the Atomic Album OK, but I do have an account already.
I tried opening the create Premium Account page and also got the error. It may be as the message says the page is being worked on.
All the Atomic Album Premium Account does is give you a unique album number for when linking to pics or uploading to it.
Did you login with your username and password at the Atomic Album home page?
You could ask on the Site Admin sub-forum (first one at the top. If there is a problem.
I do know you can link to photos from external sites but sadly do not know how to do it. Is there specific instructions on the imageshack home page as to what format to use?
Can you go to one of the posts from a member you know uses imageshack and click on Quote in that post. This will start a reply panel with the post quoted and the image as the code used to link to it. Maybe you can get pointers from that. Do not submit the reply for obvious reasons, unless you want to ask the poster how to link to image shack.
Sorry I could not be of more help.

Don't worry there are those who can.
Good luck
Doug
P.S. Your update crossed my reply. I'll leave it here in case it helps anyone else.