Can't Edit Define Main Page in Define Page Editor

I can't edit the main page in the define pages editor. I did yesterday with no problem but today I'm getting an error message that I don't have permission. Also a 404 message.

I can edit everything else in the define page editor. My permissions are set right from what I can see. In my FTP they are set at 755. I do not know where else to look or what to do. Help Please.

http://ididitcreations.com/shop

Thank you
Robyn

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Other Post
http://www.zen-cart.com/forum/showthread.php?t=154471

Sorry I thought that was a closed question as no one was answering it. I see there are so more remarks there. Thanks