Is your MLS feeding the data through something like www.listhub.com or www.point2.com?
If not I suggest your broker signing up for these services - they're mostly free.
Also - it could be a problem with your site not pulling the data through.
So many things
USUALLY I say in answer to this - "Mr/Mrs Seller I am making sure that the information that is publicly shown is perfect and this takes a few hours. I'd rather make sure your home is represented in the VERY best light than just throwing it up there and hoping"